Coventry moved five points clear at the top of the Sky Bet Championship after fighting back to beat Sheffield United 2-1 at Bramall Lane.
Harrison Burrows' deflected effort gave the Blades a deserved lead early in the second half before Frank Lampard's side struck twice in five minutes to give their title hopes a major boost.
Haji Wright equalised four minutes after Coventry had fallen behind and Jack Rudoni's header sealed their third straight win.
The Sky Blues, who held a 10-point lead at the top in November, were knocked off top spot by Middlesbrough earlier this month, but have regained momentum in their bid for a top-flight return for the first time in 25 years.
The Blades, who remain nine points adrift of the play-off places, were made to pay for a string of missed first-half chances.
Chris Wilder's side made an impressive start. Gus Hamer's dangerous low cross was parried wide by Coventry goalkeeper Carl Rushworth and, from the resulting corner, Andre Brooks' shot was deflected narrowly off target.
Rushworth held Burrows' thumping effort and it was 15 minutes before Coventry first threatened as Rudoni's cut-back was scrambled clear.
Chances for Coventry pair Wright and Tatsuhiro Sakamoto were both snuffed out and, in an end-to-end opening 20 minutes, Patrick Bamford fired straight at Rushworth from inside the penalty area.
Both sides continued to carve out chances as Brooks' touch deserted him in the box before Wright was thwarted at the far post in the opposite area by Femi Seriki following Milan van Ewijk's cross.
Blades midfielder Djibril Soumare lashed a shot over the crossbar and Callum O'Hare headed Burrows' free-kick wide as the home side finished the first half on top.
And the Blades were furious just before half-time when referee John Busby was unmoved after Seriki had gone down in the area under Ephron Mason-Clark's challenge.
The Yorkshire club resumed on the front foot and took a deserved lead three minutes after the restart.
Burrows ran on to Hamer's clever reverse pass into the area and his shot was deflected into the roof of the net to give his side a deserved lead.
Coventry had been second best but they launched a speedy response, scoring twice in five minutes to turn the game on its head.
Wright stepped inside on the left edge of the Blades' area and fired home a right-footed shot for his 14th league goal of the season and Rudoni headed home Mason-Clark's cross in front of the jubilant travelling fans.
Hamer curled a 25-yard effort just wide for the Blades and Sky Blues winger Sakamoto forced home goalkeeper Michael Cooper into a sprawling save.
Referee Busby incensed home fans again, booking Blades substitute Tyrese Campbell for diving after he had tumbled in the area and although the hosts pressed for an equaliser, Coventry held firm.
Sheffield United's Chris Wilder:
"When you play as well as we have played tonight, you have got to win the game and we haven't.
"And I suppose, from Frank and Coventry's point of view - they said, 'we've not been great, but we've ended up winning the game'.
"I wish them all well and all the best. I think they'll obviously go on now to play in the Premier League next year and nights like tonight cement that."
Coventry's Frank Lampard:
"We're happy because there's lots of ways to win a game. We've won some games in a beautiful fashion this season and when you win games like tonight, they feel just as good.
"But we all go back tonight and we will sleep well, then we get up and go again tomorrow, because this league is such a challenge.
"The minute you think you might have cracked it, you haven't. Stoke (at home on Saturday) will come around quickly.
"It was important that we kept calm and we kept working. And the boys, to be fair, have done that and now we've got pretty much fully-fit squad.
"This league will kick you if you get relaxed, but these last three games have obviously been very good for us."
