Saracens won a pulsating meeting with Harlequins to secure home advantage in the Premiership semi-finals.
England's Owen Farrell kicked 11 points and Sarries ran in five tries in front of more than 55,000 fans at Tottenham Hotspur Stadium.
Quins replied with four of their own, two from in-form Cadan Murley, but Saracens recorded a sixth straight league win over their rivals
The visitors' top-four hopes look slim as they stay eighth in the table.
Harlequins made a dream start as England number eight Alex Dombrant barged over inside two minutes after Danny Care took a quick penalty.
The game was turned on its head 12 minutes later, however, as Spurs fan Alex Lozowski collected Ben Earl's offload to nip through by the posts and his fellow centre Nick Tompkins finished a flowing move soon after.
Ivan van Zyl needed assessment for a head injury after a collision with Care, who was sin-binned for the first time this season after taking an illegal swipe at the ball.
Farrell made Quins pay by slotting the resulting penalty to make it 17-7 but missed the conversion after Andy Christie dived over in the corner to end another slick move just before the interval.
Three minutes after the turnaround Murley powered over in the corner after a fizzing pass from Marcus Smith, who then reduced the arrears to 22-14 with his second conversion.
Sean Maitland snuck over after some more slick handling just before the hour, with Farrell kicking Sarries 29-14 ahead, but Quins refused to go quietly and Murley barrelled over for his league-leading 13th try of the campaign.
Luke Northmore went into the bin for a trailing arm to the face of Farrell and seconds later Maro itoje plunged over following a lineout.
Farrell made it 36-19 before limping off with an ankle injury but Quins had the final say as former footballer Care's cross-field kick allowed Joe Marchant to pluck the ball out of the air and dot down.
Sarries director of rugby Mark McCall told BBC Radio London:
"It was a great atmosphere. The game kind of lived up to it.
"I wasn't sure how we were going to be, we had a number of players coming back after a significant amount of time away. I thought we would be disjointed but we had high expectations about our intensity and energy and for the most part that was good.
"Overall it was a good step forward for us. It was a good reaction to an early setback. To have secured it with three games to go is down to the whole squad, the 48 players we have used across the 17 games.
[On Owen Farrell being a doubt for the Champions Cup] "I think he's just aggravated the ankle he aggravated with England. I don't know how that's going to be next week, we have to wait and see.
Harlequins head coach Tabai Matson told BBC Radio London:
"The reason they are top is because they have quality across the park. Before the game we talked about how we'd need to deliver one of our best games if we were going to compete.
"We were off it a little bit at the breakdown. At the start of both halves we did quite well but then petered out. We'll rue the missed opportunities to make it tough for them right until the end.
"It was cool to be part of the extravaganza but it was always going to come down to rugby and we didn't match up.
"We're not out of the Premiership [play-offs-race], but it just got harder."
Saracens: Goode; Malins, Lozowski, Tompkins, Maitland; Farrell (capt), van Zyl; M Vunipola, George, Riccioni, Itoje, Tizard, Christie, Earl, B Vunipola.
Replacements: Dan, Mawi, Clarey, Isiekwe, Wray, Davies, Taylor, Lewington.
Harlequins: David; Marchant, Northmore, Esterhuizen, Murley; Smith, Care (capt); Marler, Walker, Louw, Herbst, Lamb, Kenningham, Chisholm, Dombrandt.
Replacements: Riley, Baxter, Collier, Hammond, Evans, Steele, Allan, Beard.
Referee: Luke Pearce