Saracens gradually saw off Harlequins to keep their dreams of winning the double alive with a 31-17 victory at Allianz Park.
The lead was evenly shared up until the 60-minute mark, with the league's best side stretching away in the late May sunshine as Harlequins faded in a bruising encounter. Saracens scored 20 unanswered points in the second half.
A total of 14 possible points went begging as kickers Owen Farrell and Marcelo Bosch toiled with the conditions and their accuracy, but they were not made to pay in the end.
Saracens' domestic dominance has been unrivalled - their only loss at home all season, to London Irish, was freakish - but they took some time to get going.
In the end they scored three tries, England winger Chris Ashton making sure of the result and that there would be no repeat of last season's shock loss to Northampton on home soil.
They will have to raise the performance displayed in the first 60 minutes by many levels compared to this to compete with Toulon in next week's Heineken Cup Final.
Harlequins had more or less been written off by all parties before kickoff, having snuck into the 4th spot. Conor O'Shea pre-match inspiration speech therefore had already been written and his team came out with a fire in their belly.
Tension was omnipresent throughout the opening exchanges as Owen Farrell and Nick Evans traded penalties, with the England fly-half's touchline break bringing the game to life only for it to end with no reward.
Friday's semi-final was dominated by the TMO and an early call to action was required after Kyle Sinckler was sent into a forward flip following a tackle from Schalk Brits. The outcome to not award a penalty or card may have irked some Harlequins fans, but felt like the right call.
Farrell put his team into the lead for the first time with a second penalty on his third attempt, after his second effort had clattered back off the post.
Tempo was difficult to create. Harlequins thrive off playing quicker than their opponents and making them work to fill spaces, but their forwards couldn't build the momentum.
It's something they've done so well this season, spearheaded by Nick Easter on his record appearance for the club, but early on they were stalling.
Brits may not have been penalised for a tip tackle but Marcelo Bosch was, yellow carded for lifting Evans and driving him into the ground. Evans recovered to try and land his second penalty but sent it wide down the right.
Physicality was overcoming skill as the game pondered through to the half hour mark, but when Saracens went down to 13 after a careless slap of the ball down from Matt Stevens the home side were truly tested.
Step forward Ugo Monye, initially bouncing off tacklers down the left to put Harlequins behind the defensive line, before the former England winger gathered Evans' looped pass and raced over untouched.
Saracens would inevitably respond, and they did in style. Kelly Brown had the presence of mind to outpace Charlie Matthews on the outside and fend him off to score. It was intelligent play from the Scotland captain to put his team back into the lead after the power runners had sucked in the defence.
Perhaps Harlequins had missed their chance to win this one, ending their two-man advantage with Saracens in the lead.
Good defensive pressure handed them a gift as the blitz on Alastair Hargreaves forced the ball loose, Harlequins hacking on into space for Mike Brown - the best player in England - to dot down. Evans converted to give the underdogs a 17-11 lead at half-time.
Saracens wasted little time to try and claw back at the deficit with a rolling maul that produced a penalty, but Farrell's radar was switched off as he missed his third kick of the afternoon.
Bosch was also struggling, missing his second strike as Saracens started to wonder if the gods were in their favour. Danny Care's drop goal ricocheting back off the post gave them a sign.
In fact as a result of the scramble for ball after Care's attempt, Saracens marched down the other end of the field to win another penalty. Farrell pumped it into the corner.
Brad Barritt couldn't be held back by the defence as he shook off some poor tackles to go over for the posts, Farrell's conversion restoring the lead for the home side.
A further free from Farrell gave Saracens a slither of daylight at 21-17, one they nearly drew a line under only for Bosch to be ruled offside before he raced away to score.
Harlequins looked drained as Saracens persistently breached their defensive line. Brave as Conor O'Shea's men had been they couldn't hold out forever.
Chris Ashton landed the biggest punch of the match to date after some stellar interplay from Brown and Barritt to release the finisher to the line, for his 19th score of the season.
Mike Brown's withdrawal will concern Stuart Lancaster and added insult to injury for Harlequins, whose number of walking wounded was beginning to grow as Monye also departed.
The rousing reception for Steve Borthwick on his final outing was fitting with the result sewn up, another Farrell penalty tipping Saracens over the 30-point mark. The shot at the double is on.
Tries: Brown, Barritt, Ashton
Cons: Farrell 2
Pens: Farrell 4
Yellow Cards: Bosch, Stevens
Tries: Monye, Brown
Cons: Evans 2
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Marcelo Bosch, 12 Brad Barritt, 11 David Strettle, 10 Owen Farrell, 9 Neil de Kock, 8 Billy Vunipola, 7 Jacques Burger, 6 Kelly Brown, 5 Mouritz Botha, 4 Steve Borthwick (c), 3 Matt Stevens, 2 Schalk Brits, 1 Mako Vunipola
Replacements: 16 Jamie George, 17 Richard Barrington, 18 James Johnston, 19 Alistair Hargreaves, 20 Jackson Wray, 21 Richard Wigglesworth, 22 Charlie Hodgson, 23 Chris Wyles
Harlequins: 15 Mike Brown, 14 Tom Williams, 13 Tim Molenaar, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (c), 6 Luke Wallace, 5 George Robson, 4 Charlie Matthews, 3 Kyle Sinckler, 2 Dave Ward, 1 Joe Marler
Replacements: 16 Rob Buchanan, 17 Mark Lambert, 18 Will Collier, 19 Nick Kennedy, 20 Tom Guest, 21 Karl Dickson, 22 Ben Botica, 23 Sam Smith
Referee: Wayne Barnes
Assistant Referees: Robin Goodliffe, Roy Maybank
TMO: Graham Hughes
by Ben Coles