Leicester will carry a 1-0 lead to Watford in the Championship play-off semi-final second leg courtesy of David Nugent's first goal in 17 games that settled the first leg in the home side's favour.
Nugent popped up on 82 minutes to head home the only goal of an engrossing first leg at the King Power Stadium from Antony Knockaert's free-kick as Nigel Pearson's men pulled a victory out of the fire.
Gianfranco Zola's Watford host the return leg at Vicarage Road on Sunday afternoon with Leicester carrying that slender advantage as they aim to book a place in the play-off final at Wembley.
Watford had won their last three clashes with Leicester City in the league.
That included two 2-1 victories over them this season, but they lacked a killer instinct in the final third of the pitch that buried their hopes of earning a draw that should not have been beyond them.
Ritchie De Laet started for Leicester with Paul Konchesky on the bench. Right-back De Laet limped out of Saturday's thrilling 3-2 victory over Nottingham Forest after a kick on the calf while left-back Konchesky underwent a minor hernia operation last week and missed the trip to the City Ground.
Goalkeeper Manuel Almunia pulled out of the final-day defeat by Leeds after feeling his hamstring in the warm-up but was fit for action. Alexandro Geijo replaced Fernando Forestieri for the visiting side.
Nugent forced Almunia to make a smart stop from a back-heel on three minutes before the former Arsenal man held a powerful De Laet header 10 minutes later.
Kasper Schmeichel made two impressive saves to halt efforts from Iketchi Anya and Almen Abdi as the game sped from end to end.
Nugent somehow managed to flick a shot wide of goal from 12 yards out on 25 minutes from Lloyd Dyer's pass while Andy King threw himself at the ball to block a shot from Anya after he had been played in by Marco Cassetti.
Watford were easier on the eye, but Leicester's work ethic continued to unsettle the visitors as Knockaert gave Cassetti the slip on 40 minutes but Almunia was alert to make a fine stop.
Matej Vydra then squandered a superb chance on 59 minutes when he knocked the ball into the ground and straight at Schmeichel with the Leicester defence AWOL.
Schmeichel showed his quality to repel a stinging effort by Vydra seconds later as it appeared the game would end without a goal until Nugent's perseverance finally paid off.