HARLEQUINS beat Bath 19-16 to climb above their opponents into fourth place and snatch an Aviva Premiership play-off spot on a nail-biting final day at the Stoop.
The victory is Quins' fifth on the bounce and completes a remarkable comeback for Conor O'Shea's side who have also beaten Exeter, Leicester, Sale and London Irish en route to the knock-outs.
They now face a trip to table-toppers Saracens in the semi-finals.
The home side knew a bonus-point victory would see them jump above Bath as would a victory of any kind so long as the visitors were restricted to one bonus point or less.
Mike Brown gave the hosts a dream start with an early try but his effort was cancelled out by George Ford's excellent solo effort and it was only Nick Evans' penalty that gave Quins a 10-7 lead at the break.
The second period became a battle of the kickers as Matt Banahan's yellow card prompted Quins to take a 16-10 lead and three penalties - two from Ford - left the home side just three points ahead with 10 minutes to play.
Bath pressed and probed in the dying moments, eager to find an opening, but Ford's desperate drop-goal attempt fell short and confirmed Quins' place in the semi-finals.
Both sides started nervously but Ford seemed at ease from the outset as he made his first dart through the Quins back-line in the 12th minute only to see his kick through blocked by Brown.
The home side started to find some rhythm and just after the quarter-hour mark scored the first try of the game as Danny Care flung a superb looping pass out to Brown who slid over in the corner.
Evans converted from just inside the left touchline to put Harlequins 7-0 ahead.
The lead lasted less than five minutes, though, as Ford scored a brilliant solo try, weaving his way through a hesitant Harlequins defence to go over before adding a simple conversion to make it 7-7.
Moments later, the home side thought they had restored their advantage as Care broke through Leroy Houston's tackle before releasing a clever one-handed pass to Easter who touched down.
Referee Wayne Barnes suspected a forward pass however and after referring the decision to TMO, the try was ruled out.
A simpler chance to move ahead was spurned in the 32nd minute when Evans missed a straightforward penalty.
The Quins fly-half made no mistake moments later, adding three points from close-range to put the hosts 10-7 ahead at half-time.
Bath pegged their opponents back just five minutes after the break as Ford converted a simple penalty but it could have been more moments earlier when Nick Abendanon broke through but was felled just short.
The visitors were reduced to 14 soon after as Banahan was shown a yellow card and Quins almost took advantage immediately as an excellent turnover put Brown through but the England full-back was blocked by Ford.
Evans put his side back in front with his second successful penalty and extended the gap to 16-10 with another kick from the tee before the hour.
Three more penalties, two for Ford and one for Evans, made the score 19-16 with 10 minutes to play as both teams tightened up, desperate not to make a mistake that could swing the contest in their opponents' favour.
Bath patiently retained possession in the final minutes as they looked to create an opening but as the clock ticked past the 80-minute mark, Ford's missed drop-goal attempt ensured it was Quins who would progress to the play-offs.
REACTION TO BATH'S DEFEAT AT WILTSHIRETIMES.CO.UK/SPORT AND IN NEXT WEEK'S WILTSHIRE TIMES