Leicester Tigers came from behind to beat Harlequins 43-33 in a thrilling clash at the Stoop on Saturday.
Leicester's form looks ominous for the other play-off contenders as they saw off the leaders to move into second place in the standings.
The game didn't take long to get warmed up as both sides sought to lay down a marker ahead of the end of season play-offs and it was the Tigers who struck first as they turned down a potential three point opportunity and Thomas Waldrom rumbled over from the resulting line-out to open the scoring.
But, after Nick Evans had replied with two penalties to Toby Flood's one, Ugo Monye telegraphed a poor Flood pass inside his own half and raced away to score under the posts and give Quins the lead for the first time.
And with the home side on top, Manu Tuilagi was sent to the sin bin for tackling his opposite number George Lowe without the ball, allowing Evans the chance to add another three points to the total.
Harlequins made even more of their one-man advantage moments later as Nick Easter picked the ball up from the base of the scrum and smashed straight through Tom Croft on his way to the line, injuring the England man in the process.
Flood and Evans again exchanged penalties and, back up to their full complement, Leicester had the final say of the half as Steve Mafi, on as a replacement for the injured Croft, went over. The Australian-born forward picked the ball up and smashed straight through some poor defending on the fringes of a ruck.
And Flood added the conversion and a penalty with the final kick of the half to narrow the deficit to just three points at 26-23 at the break.
Flood levelled the scores early in the second half but no sooner had he done so than Lowe catapulted Quins back into the lead.
Evans created the try with a deft grubber kick that bounced perfectly into the centre's hands but both have their forwards to thank after they won a scrum against the head to provide the opportunity.
The Tigers came back again though as some incessant pressure and good breaks from Anthony Allen and Flood created an overlap which Alesana Tuilagi finished with aplomb to level the scores once more.
And Leicester's now customary late charge was completed ten minutes from time as Waldrom grabbed his second try of the game after a great break from Allen down the left and good work from Flood gave him the chance.
Flood added a late penalty to secure the win for the Premiership's form team and deny the leaders a bonus point.
Tigers now move ahead of Saracens in the table, making them favourites to claim a home semi-final.
Tries: Monye, Easter, Lowe
Cons: Evans 3
Pens: Evans 4
Tries: Waldrom 2, Mafi, AT Tuilagi
Cons: Flood 4
Pens: Flood 5
Yellow cards: M. Tuilagi (Leicester - 21st min)
Harlequins: 15 Mike Brown, 14 Ugo Monye, 13 George Lowe, 12 Jordan Turner-Hall, 11 Sam Smith, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (capt), 6 Maurie Fa'asavalu, 5 George Robson, 4 Olly Kohn, 3 James Johnston, 2 Rob Buchanan, 1 Joe Marler.
Replacements: 16 Aston Croall, 17 Mark Lambert, 18 Will Collier, 19 Tomas Vallejos, 20 Tom Guest, 21 Karl Dickson, 22 Rory Clegg, 23 Ross Chisholm.
Leicester: 15 Geordan Murphy (capt), 14 Horacio Agulla, 13 Manusamoa Tuilagi, 12 Anthony Allen, 11 Alesana Tuilagi, 10 Toby Flood, 9 Ben Youngs, 8 Thomas Waldrom, 7 Julian Salvi, 6 Tom Croft, 5 Geoff Parling, 4 George Skivington, 3 Dan Cole, 2 George Chuter, 1 Marcos Ayerza.
Replacements: 16 Tom Youngs, 17 Logovi'i Mulipola, 18 Martin Castrogiovanni, 19 Graham Kitchener, 20 Steve Mafi, 21 Sam Harrison, 22 Billy Twelvetrees, 23 Scott Hamilton.
Venue: Twickenham Stoop
Referee: Wayne Barnes