Trailing by two points inside the final minute in front of 46,013 fans, the Blues went forward through Brock McLean, whose long bomb from outside the 50-metre arc bounced through to hand Carlton victory 14.11 (95) to 13.13 (91).
Carlton small forward Eddie Betts kicked a game-high four goals while onballers Dustin Martin and Trent Cotchin scored three majors each for the Tigers.
It's the third game in a row where the Tigers (7-10) have lost by less than a goal, ending their finals hopes. The Blues improved their win-loss record to 9-8.
The Tigers led 5.2 (32) to 4.2 (26) at quarter-time after Martin and Cotchin went forward and kicked five goals between them in the opening term.
But Carlton responded strongly in the second quarter, holding Richmond goal-less and adding three majors to lead by 10 points at halftime.
Richmond were denied a goal to Shane Edwards by a video review in the second quarter when the ball was deemed to have been touched.
Carlton's Brock McLean also had a goal taken off him in the third term after Tigers defender Alex Rance claimed to have touched the ball and a behind was awarded after a video review.
The Tigers hit back after halftime with goals to Shane Tuck, Robin Nahas and Luke McGuane to move eight points clear. However the Blues surged late in the third term to hold a 12-point advantage at three-quarter time.
Onballer Tuck booted his second goal then set up another for Nahas which put the Tigers back in front by a point.
Second-gamer Levi Casboult's goal gave the Blues the lead but Richmond replied with three quick goals to move 13 points clear at the 21-minute mark.
Dennis Armfield and Bret Thornton led another Carlton rally with vital goals.
Richmond were two points up with less than a minute remaining when Steven Morris' clearing kick went out of bounds on the full, as McLean seized his chance.
Carlton were outscored four goals to five in the final term but defended grimly in the final moments, twice forcing the ball over the boundary.
Fullback Michael Jamison held Richmond's Jack Riewoldt goal-less while Blues midfielder Andrew Carrazzo ensured the influence of Cotchin faded after quarter-time.
McLean was also prominent with 27 possessions, 10 tackles and nine clearances while Marc Murphy had 36 touches for the Blues.
Carlton fielded a depleted side missing first-choice players Jarrad Waite, Lachie Henderson, Shaun Hampson, Andrew Walker, Kade Simpson, Jeremy Laidler, Mitch Robinson and suspended skipper Chris Judd.
A delighted Carlton coach Brett Ratten said his heart had been racing during the roller-coaster last quarter.
"It is very emotional, especially with what's at stake," Ratten said.
"We are getting to the pointy end of the season and there's not too many games (left) and four points are so valuable."
Ratten said to win from a 13-point deficit late in the game showed there was great spirit at Carlton.
A shattered Richmond coach Damien Hardwick watched his men lose by two goals or less for the sixth time this season.
"When we lose three games (in three weeks) by under a kick, there's some things going wrong that we've got to fix," he said.
"We're not good enough at this stage. Just basic errors that we shouldn't make."