Saracens will head into their Aviva Premiership semi-final against Gloucester on the crest of a wave after rounding off the regular season with a 16-13 win at Harlequins - their 11th consecutive victory.
Owen Farrell's second-half contribution of a try, conversion and penalty ultimately proved the difference after the two sides had been locked at 6-6.
Farrell, the teenage fly-half who started the season on loan at Bedford, is now 80 minutes from guiding Saracens into the Premiership Grand Final.
His performance was witnessed by England backs coach Brian Smith ahead of the forthcoming Churchill Cup, in which Farrell is sure to be involved.
Chris Robshaw crossed for a consolation try but it was too little too late for Harlequins, who finish seventh in the Premiership and miss out on automatic Heineken Cup qualification.
Conor O'Shea's men can still book their place in Europe's premier competition if they beat Stade Francais to win the Amlin Challenge Cup or if Northampton win the Heineken Cup.
Saracens were on course to finish the regular season top of the Premiership table until Leicester produced a dramatic comeback at Welford Road to beat London Irish.
In the end, Saracens had to settle for second place and they will tackle Gloucester at Vicarage Road next Sunday for a place at Twickenham.