Harlequins boss Conor O'Shea hailed Saracens as "absolute favourites" to win the Aviva Premiership title after their 16-13 victory at the Twickenham Stoop.
Saracens will face Gloucester in a home semi-final next Sunday on the back of 11 consecutive victories. The two sides were locked at 6-6 at the interval before Owen Farrell scored his first Premiership try, landed the conversion and then kicked a penalty to give Saracens a winning lead.
Afterwards, O'Shea tipped Saracens to beat Leicester in the final, saying: "Mentally they are the toughest side in the Premiership, they know their roles and stick to that pattern and I make them absolute favourites to win the Premiership."
He added: "I know Leicester, Gloucester and Northampton will have something to say about that but there is just something about Saracens that makes you think they will go that extra yard this year.
"They are right up there now and they have earned that right."
Saracens were three minutes away from finishing top of the regular season table until Leicester produced a dramatic late rally to beat London Irish and retain their place at the summit.
Director of rugby Mark McCall said: "It would have been a nice thing to be first past the post but I also think that winning 18 games out of 22 is one heck of an achievement.
"It is all about next week now and Gloucester will be a tough match. Gloucester are one of the most dangerous attacking teams in the Premiership.
"We have got to be way better next week."