Premiership: Harlequins 20-19 Saracens
|Harlequins (5) 20|
|Tries: Walker 2, Visser Con: Lang Pen: Lang|
|Saracens (10) 19|
|Try: Barritt Con: Farrell Pens: Farrell 4|
Saracens lost their fifth consecutive match as Tim Visser's late try handed Harlequins a pulsating derby victory.
Sarries led 10-5 at the break through Brad Barritt's converted try and Owen Farrell's penalty, with Charlie Walker crossing for Quins at The Stoop.
Two more Farrell penalties gave Sarries a 16-8 lead but Danny Care inspired a Quins comeback in the last 10 minutes.
Walker raced onto the scrum-half's kick for his second try to cut the deficit before Visser secured a dramatic win.
Harlequins deserved the victory having dominated possession and territory after going behind in the second minute when Vincent Koch's line break set up former England centre Barritt to score.
Saracens' defence repelled their attacks in the second half until a quick tap-penalty from Care created the space to chip ahead and Walker pounced on the loose ball for his second try of the game with nine minutes remaining.
Farrell, who passed 1,000 career Premiership points in the first half, kicked another penalty to make it 19-15 but there was still time for returning England back Care to set up a third try for the hosts.
His cross-kick to the left wing drew Alex Goode out of position and, with the Sarries full-back unable to gather the ball, Scotland wing Visser crossed in the corner to extend the double European champions' miserable run of form in all competitions.
Quins climb to seventh in the table while Saracens, who have lost their last three Premiership games, remain third, nine points behind leaders Exeter.
Harlequins director of rugby John Kingston:
"I'm really pleased for the group. It was a rollercoaster of a game and the belief was getting greater as the game wore on.
"We just about deserved it as we stuck at it. We knew if we were playing well we could take it to the wire.
"Saracens have a wonderful defence and that is a heck of a team we have managed to down. Every time you win you have to savour it as they are the European champions and still the litmus test."
Saracens director of rugby Mark McCall:
"We are hugely disappointed as we were the masters of our own downfall. We chucked away a victory by not being bright and intelligent enough.
"We put a huge amount of effort in but ultimately it was wasted. Our defence was in charge of their attack for large periods.
"It is always concerning when you lose games you should have won. We gave away some terrible penalties on the halfway line and put ourselves under pressure."
Harlequins: Brown; Walker, Alofa, Roberts, Visser; Lang, Care; Marler, Elia, Collier, Merrick, Horwill (capt), Bothma, Robshaw, Luamanu.
Replacements: Ward, Boyce, Sinckler, Lamb, White, Kitto, Prior, R. Chisholm.
Saracens: Goode; Maitland, Bosch, Barritt (c), Wyles; Farrell, Wigglesworth; M. Vunipola, George, Koch, Isiekwe, Kruis, Itoje, Clark, Wray.
Replacements: Tolofua, Barrington, Figallo, Skelton, Burger, Spencer, Lozowski, Earle.
Referee: Luke Pearce.