Quins top, Tigers go second
London Irish were dragged deeper into the relegation mire after champions Harlequins ground out a 26-15 victory in the Aviva Premiership.
The Exiles were in touch for 78 minutes in front of 82,000 fans at Twickenham, but left empty-handed after a late penalty try from Harlequins' dominant pack denied them a losing bonus point.
Harlequins had taken the lead after a scrappy first half with a try from scrum-half Danny Care and Nick Evans added 16 points with the boot.
Ian Humphreys booted all of the Exiles points, but it was not enough.
Leicester fought off a rousing finish from Gloucester to win a thrilling match 17-12 at Welford Road and jump two places to second.
Trailing by five points Gloucester threw everything at Leicester in the final few minutes and were twice thwarted by the Tigers' last ditch defence on the line.
Anthony Allen scored the only try of the match against his former club seven minutes after half-time following intense pressure from a Leicester pack that dominated a match in which four players were yellow carded.
Leicester's other points came from fly-half George Ford, who kicked three penalties, and Geordan Murphy who added another. Fly-half Freddie Burns slotted over four for Gloucester.
The conversion of a penalty try three minutes from time denied Exeter their first Premiership victory over west country rivals Bath in front of a sell-out crowd of 10,744 at Sandy Park.
The visitors scored the game's first try in a 12-12 draw, started and finished by scrum half Michael Claassens in the left corner with great support play from wing Tom Biggs and fly-half Steven Donald. Claassens was unable to convert from touchline.
Gareth Steenson landed four kicks for the hosts but Bath then won a penalty late on inside the Exeter 22 and opted to kick for the corner, with the Chiefs penalised at the ruck.
Bath repeated the move and referee David Rose awarded a penalty try. Tom Heathcote added the extras to level the scores.
A brilliant try from scrum-half Joe Simpson was the highlight of London Wasps' bonus point 34-15 victory as they did the Aviva Premiership double over London Welsh .
Simpson had an outstanding game as Wasps came from behind with tries from wing Elliot Daly, replacement prop Will Taylor and, right at the end, a fourth try for wing Tom Varndell.
Welsh fly-half Gordon Ross kicked all his side's points with five penalties, while Wasps fly-half Nicky Robinson landed three penalties, Daly booted one and replacement stand-off Stephen Jones kicked the only conversion of the match.