Don't forget you can watch highlights of this match, along with every Premier League game, from 00:01 on Monday morning (UK only).
The final whistle goes and Samir Nasri's goal sees the champions get their title defence off to a winning start. Southampton may have lost, but they showed enough here to suggest that they will have plenty of hope of staying up this season.
Three minutes of added time are signalled by fourth official Mark Clattenburg.
Manchester City substitution: Aleksandar Kolarov replaces Tevez.
Schneiderlin is booked for a cynical foul that stopped a City counter-attack.
Southampton substitution: Billy Sharp replaces Puncheon.
Nasri was booked for revealing a message on his t-shirt when he scored. He must have lifted his shirt all the way over his head, unlike Tevez earlier who did not receive a yellow card.
Nasri scores his sixth league goal for City since joining them last year. All of his previous five goals have come in victories.
GOAL!! City are ahead! Clichy's cross is inexplicably headed back across goal by Danny Fox and Nasri is on hand to fire City back into the lead!
Toure bends an inviting cross to the near post where Dzeko heads wide! Chances coming thick and fast now.
Yaya Toure's free-kick is parried by Kelvin Davis and Southampton's defenders react quickest to clear.
The last time City lost a league game at home was against Everton in December 2010.
The last team to lose in their opening match of the season as defending champions was 23 years ago, Arsenal losing 4-1 at Man United in 1989.
End-to-end stuff now as a Southampton attack is snuffed out and a City break ends with Balotelli htting the side-netting!
GOAL!! A City corner is headed away but only as far Kompany. The captain's shot rebounds off Toure's legs but Dzeko is at the far post to finish!
Manchester City substitution: Mario Balotelli replaces Silva.
In the second half so far City have had 81% of the possession, and yet they are losing 2-0 in that time.
Former Villa and Fulham midfielder Davis is easily the most experienced player in the Southampton team when it comes to Premier League football, with 113 appearances in the top flight before today.
GOAL!! From that break Southampton go ahead! The cross fromt he left of blocked but Steven Davis, another substitute, lashes a low strike across Hart and into the bottom corner!
Tevez's shot deflects off the wall for a corner. Nasri's delivery is headed clear and Southmapton can break after Rodwell's sloppy pass.
City win a free-kick in a great position for someone to shhot. After a mini-summit around the dead ball, it will be Tevez to strike.
Southampton substitution: Steven Davis replaces Ward-Prowse.
Not sure what happened, but Fox was booked for something he did during the celebration of that Lambert goal.
Southampton fans doing the Poznan at the Etihad. No points for originality but they deserve to enjoy the moment.
Having scored 77 league goals in his three years at Southampton, he now scores their first goal back in the top flight! That's why they love him at St Mary's.
GOAL!! Just three minutes after coming on, Lambert equalises! Last season's top scorer shows great instinct to pounce on a loose ball on the edge of the box and curl a well-struck finish past Hart!
Yaya Toure leads the charge on the break and it's three v three. Toure plays it right to Tevez who skews his strike well wide of the target. So wide, in fact, and Silva thought it was a corner and jogged over to take it!
Neat feet from Puncheon to work a yard of space and get his cross in from the right and Adam Lallana steals in but guides it wide from an awkward angle.
Southampton substitution: Rickie Lambert replaces Rodriguez.
Tevez again drives into the Southampton box. His strike is palmed away by Davis and Nasri tees it up for Silva, who fires over the bar!
City scored the highest percentage of second half goals in the Premier League last season (68%). However, Roberto Mancini’s side also conceded the highest proportion of second half goals (79%).
Yaya Toure sees Clichy's run in behind Clyne and pings a diagonal pass into his path, but it bounces just in front of the left-back and goes over the bar.
Brilliant play from Nasri as he wriggles and turns his way past two Southampton defenders at the byline. He fires a low ball across the box and Dzeko somehow manages to not guide it home! A great chance to double City's lead goes begging.
The word from the City medics is that Aguero will have a MRI scan on his ankle, but they reckon that is more a precautionary measure than anything. Encouraging news.
The second half is underway!
The whistle goes for half-time, and City go into the break with a one-goal lead.
Tevez attacking down the right flank now and his low cross is headed for Yaya Toure but it rebounds off the legs of a defender.
A nervy end to the half for Southampton as City set up camp in their half.
Four minutes of Aguero-induced injury time to be added at the end of the first half.
Dzeko drags a low shot right at Davis who saves and manages to keep hold of the ball at the second attempt.
Nasri tries another clever ball lifted over the top, this time bound for Zabaleta, but the right-back had checked his run for fear of straying offside.
Tevez celebrates his 49th Premier League goal for Manchester City by revealing a t-shirt bearing the message "Lugano - 1 v 2". Any ideas what that means, anyone?
GOAL!! Nasri clips a ball over for Twevez who lets it rolls past him before dispatching a clinical low finish inside the near post!
Both of Southampton's centre-backs - Hooiveld conceding the penalty aside - have been great so far. City have hardly had a clear-cut chance despite having around 60% of the possession.
Lallana's free-kick clips off Nasri's head and Saints have their second corner of the game. The officials decide it came of Rodriguez before going wide, so it's a goal kick.
Tevez again instrumental as City break, but his threaded pass through to Dzeko doesn't find its target. Zabaleta blocks a Southampton cross with his arm and concedes a free-kick in a useful area.
Another good tackle by Fonte, this time on Silva after the Spaniard was played into the area by Zabaleta.
Clever play from Tevez whose movement on the edge of the box keeps Southampton's defenders guessing. His lets a shot fly but it rolls right to Davis.
Clichy's cross is turned behind for a corner by Fonte. Nasri's delivery goes all the way to the other flank where Joleon Lescott keeps it in play.
A good passage of play from City ends with a cross from the right that is just too high for Dzeko. So you know it must have been high.
Tevez is sent away down the left but he is stopped in his tracks by a good tackle from JOse Fonte. Tevez wants a free-kick but referee Howard Webb is not interested.
The ball has hardly left the centre of the pitch over the last few minutes. both teams taking their turn to win possession, move forward, lose possession and repeat.
Silva’s miss was Man City’s first in seven penalties in the PL, since Carlos Tevez missed in a 3-0 home win against Wigan in September 2011.
Clyne looks to go off on a run down the right but he is stopped by a timely tackle from Nasri of all people.
Yaya Toure loses the ball in midfield but City soon have it back. They are faced with a well-organised barrier of red shirts.
Wonder if Roberto Mancini is thinking he should have brought Mario Balotelli on instead of Dzeko. The Italian striker is yet to miss a spot-kick for City.
Tevez skips across the edge of the box but can;t work the space for a shot. Well defended there by Southampton, who are coming under real pressure now.
That really was a poor penalty from Silva, perhaps even worse than Shane Long's for West Brom yesterday. Of course, West Brom still went on to win that game against Liverpool 3-0.
SAVED BY DAVIS!! It was an awful penalty from the Spaniard, rolled tamely and too close to the keeper!
PENALTY!! Samir Nasri flicks a backheel into the area and Tevez is tripped by Jos Hooiveld as he rolls past the defender!! David Silva will take it...
Manchester City substitution: Edin Dzeko replaces Aguero.
After it initially looked as though Aguero would be OK, he is now being stretchered off and will play no further part. Applause comes from all sides of the ground.
Morgan Schneiderlin has a low strike flash wide after good work from Guly in the City area.
Aguero gets back on his feet, and it looks like he will be OK to continue. Relief on the face of City fans and fantasy football players everywhere!
Not looking good for Aguero, who is not the sort of player to make a big deal out of a knock.
Aguero appears to be in some pain following that challenge. The City physios are giving plenty of attention to his ankle. Mario Balotelli is warming up now.
City defend the set piece and hit Southampton on the break. Sergio Aguero storms down the ptich but he's taken out by a great sliding tackle from Nathaniel Clyne on his Southampton debut.
James Ward-Prowse brigns the ball forward with confidence before popping it off to Guly do Prado who is fouled by Vincent Kompany.
Gael Clichy's rather aimless cross is headed well clear by Danny Fox.
Tevez just strayed offside as he receives the ball wide on the left. He knows he should have stayed level there, he could see down the whole Southampton back line.
Some early possession in the city half for Southampton. Jay Rodriguez comes out to the left otuchline to get some early touches of the ball.
Silva assisted the most goals in the Premier League this season, 15.
David Silva, like James McClean yesterday, has to be hauled off to have his socks re-taped with tape that is of the same colour. Thanks for that new directive, FIFA.
City kick off and we're underway!
The players are out on the pitch now, shaking hands. We'll be underway in moments. you cna share your thoughts on the game with me via Twitter @tony_mabert.
In case Ward-Prowse feels daunted by the prospect, yesterday Fabrice Olinga scored the winner in Malaga's 1-0 win at Celta Vigo in La Liga, and he's only 16.
Today is a special day for Southampton's James Ward-Prowse. The 17-year-old is making his league debut for the club at the home of the champions.
Only three of Southampton’s starting XI have previously played in the Premier League before today – Kelvin Davis (33 appearances), Daniel Fox (14), and Jason Puncheon (13).
Premier League action has already taken place today, with European champions Chelsea striking twice early on to defeat Wigan 2-0 at the DW.
Before yesterday's games just one newly promoted side (Blackpool vs Wigan) had managed to win their opening Premier League game in the last three seasons (W1 D1 L7), while only two have scored.
In 16 Premier League meetings between the two sides there have only been four home wins, with seven victories for the side playing away from home.
Nigel Adkins: "Not everyone was expecting us to do as well as we did in the Championship, but we were in the top two all season – on merit. Yes, we're going to the next level, but there's a stability here that should give us strength. You can't underestimate team spirit. We have to go into the Premier League with the belief that we can be strong. Aiming for 17th place is wrong; if you just fall short, there is a consequence. Aim higher, and if you fall short of that you've done all right."
Roberto Mancini: "Yes, for sure (United are title favourites), and I was serious when I said this last week because United have played for the title always, every year for 20 years. Although we won the last championship, we can't change this in one year. For this reason, I think they are favourites for the title, and now they have Van Persie - he is a really top player, the best striker last year. With Wayne Rooney, they will have one of the best couple of strikers in the Premier League."
TEAMS - Manchester City: Hart; Zabaleta, Kompany, Lescott, Clichy; Yaya Toure, Rodwell; Silva, Tevez, Nasri; Aguero. Subs: Pantimilion, Kolarov, Savic, De Jong, Milner, Balotelli, Dzeko. /// Southampton: K.Davis; Clyne, Fonte, Hooiveld, Fox; Ward-Prowse, Schneiderlin, Lallana; Puncheon, Guly; Rodriguez. Subs: Gazzaniga, Lambert, S.Davis, Sharp, Richardson, Shaw, Seaborne.
Good afternoon and welcome to our LIVE Premier League text coverage as 2011-12 champions Manchester City get their title defence underway by welcoming newly-promoted Southampton to the Eithad. The teams are in, and £15 million signing Jack Rodwell starts. Here are the full line-ups...