England fly-half George Ford kicked a 77th-minute penalty to snatch a 16-15 victory for Leicester in a pulsating Aviva Premiership match against Wasps at Welford Road.
The Tigers, who scored one try through Graham Kitchener in the third minute, trailed 15-7 from the 25th minute.
But Ford kicked three unanswered penalties in the second half despite Wasps' dominance.
England winger Elliot Daly scored both tries for Wasps, who spurned several other opportunities, while Leicester pulled off an unlikely win despite losing Nick Malouf and Telusa Veainu to the sin bin.
Both sides blew gilt-edged chances in the first half and Leicester lost England backs Jonny May and Manu Tuilagi early on, while Wasps winger Daly needed oxygen after dislocating a finger.
Leicester, who recalled May, George Ford and Dan Cole after the NatWest 6 Nations, made the perfect start, with lock Kitchener scoring in the third minute from a line-out and drive.
Ford kicked the touchline conversion but then missed a 38-metre penalty from in front of the posts before scrum-half Sam Harrison missed out on a try after a great move sparked by Matt Toomua.
Harrison, who had players outside him, was collared on the line by his opposite number Dan Robson and it proved a crucial miss.
Instead of being 16-0 ahead Leicester, who lost Tuilagi and May in the 12th minute, conceded two tries as Wasps turned the screw for the rest of the half.
Daly had a simple run-in in the 14th minute after some fierce pressure on the line, and after Jimmy Gopperth kicked a penalty and Tigers replacement Malouf was sin-binned for a high tackle, he scored his second after a great break by centre Juan De Jongh.
Danny Cipriani's touchline conversion made it 15-7 but Wasps' Robson and Leicester's Toomua both blew great chances to score, and Robson was chased down by Mathew Tait after an interception.
Wasps, who had Christian Wade, Joe Launchbury and James Haskell back from England duty, almost scored at the start of the second half before Ford put Leicester back in it with a penalty.
Leicester were boosted when England prop Ellis Genge made his comeback after injury in the 47th minute but full-back Veainu was then yellow carded for a deliberate knock-on.
Ford's 70th-minute penalty made it 13-15 and he put them ahead with another in the 77th minute.