England duo Chris Ashton and Owen Farrell led Saracens to the last four in the Heineken Cup with a 27-16 victory over last year's beaten finalists Ulster at Twickenham on Saturday.
Flyhalf Farrell kicked 17 points and Ashton scored the second-half try that killed off Ulster's hopes of a comeback and guaranteed Sarries a semi-final place for only the second time.
Ashton produced the moment of the match in the 63rd minute, cutting inside to take England team mate Brad Barritt's well timed pass and finishing off a 30-metre burst with his trademark dive across the line.
Farrell continually kept Ulster at bay, booting five penalties and one conversion as Saracens earned a last four clash with either Toulon or Leicester, who play on Sunday.
"Our forward pack was outstanding," Farrell told Sky Sports. "It wasn't tidy or clean but we got off the line and caused them problems. And if we missed a tackle there was always someone there to cover."
Ulster's South African scrumhalf Ruan Pienaar kicked 11 points, but missed two early penalties, and Iain Henderson's try in the dying moments was nothing more than a consolation for the Irish side in front of a 37,888 crowd.
Saracens had taken control of the match in the 33rd minute when they capitalised on a dubious decision to award them a lineout after the ball appeared to come off Ernst Joubert last.
The English Premiership leaders drove Will Fraser over the line in a rolling maul and, although referee Roman Poite referred the touchdown to the television match official, the try was given.
Farrell converted to give his side a 16-6 halftime lead, and two more Farrell penalties to Pienaar's one early in the second half extended Sarries' advantage to 13 points before Ashton's decisive contribution.
Earlier on Saturday, title favourites Clermont Auvergne beat Montpellier 36-14 to set up a semi-final clash with either Harlequins or Munster, who meet on Sunday.
The semi-finals take place on April 27-28.