Saracens head into the play-off phase of the Aviva Premiership season on the back of a hard-fought 16-13 win over Harlequins.
Saracens took their winning run in the Premiership to 10 matches at the Twickenham Stoop.
Owen Farrell scored ten points to take Saracens to victory, but Sarries end the season in second place after Leicester Tigers' dramatic late comeback against London Irish.
Saracens will face Gloucester in the play-off semi-finals.
Harlequins must now win the Amlin Cup to assure themselves of a Heineken Cup spot next year, or hope Northampton win the competition this season, after finishing in seventh place.
Saracens were the first to get points on the board in a closely fought first-half, with full-back Alex Goode slotting over his first penalty after 15 minutes.
Goode added another five minutes later to increase the away side's lead but missed two further kicks, which allowed Harlequins to tie up the game at half-time.
Rory Clegg made no mistake with either of his kicks and the game was level at 6-6. Saracens came out the second half the better side and got their reward with a 51st-minute try through fly-half Owen Farrell. Farrell converted himself to give Saracens a 13-6 lead, and he added another three-points on the hour mark to increase the gap to ten points.
The game looked dead-and-buried at this point, but Quins ended on top and Chris Robshaw ploughed over the line for their first try. Benjamin Urdapilleta added the two points to set up a tense finale, but Quins could not find the try that would have taken them into sixth position and Saracens held on for the victory.
Pens: Clegg (2)
Pens: Goode (2), Farrell
Harlequins: 15 Mike Brown, 14 Gonzalo Camacho, 13 George Lowe, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Rory Clegg, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (capt), 6 Maurie Fa'asavalu, 5 George Robson, 4 Ollie Kohn, 3 James Johnston, 2 Matt Cairns, 1 Ceri Jones.
Replacements: 16 Rob Buchanan, 17 Mark Lambert, 18 John Andress, 19 Pete Browne, 20 Luke Wallace, 21 Dave Moore, 22 Ben Urdapilleta, 23 Ross Chisholm.
Saracens: 15 Alex Goode, 14 David Strettle, 13 Chris Wyles, 12 Brad Barritt, 11 James Short, 10 Owen Farrell, 9 Neil de Kock, 8 Ernst Joubert (capt), 7 Andy Saull, 6 Jacques Burger, 5 Mouritz Botha, 4 Hayden Smith, 3 Carlos Nieto, 2 Schalk Brits, 1 Matt Stevens.
Replacements: 16 Jamie George, 17 Rhys Gill, 18 Petrus du Plessis, 19 Steve Borthwick, 20 Justin Melck, 21 Richard Wigglesworth, 22 Nils Mordt, 23 Noah Cato.
Referee: Tim Wigglesworth