London Irish ended Saracens' unbeaten start to the English Premiership season with a 29-20 win on Friday in a match where both teams had a player sent off.
With newly-appointed England coach Steve Borthwick watching on from the stands, his old club suffered a first defeat in 10 league games.
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London Irish captain Adam Coleman was first to be dismissed, seeing red in the 16th minute for charging into the head of Saracens hooker Tom Woolstencroft, who received lengthy treatment before being carried off on a stretcher.
Saracens flanker Ben Earl was then sent off 15 minutes later for a high tackle on Tom Pearson.
Amid a flurry of cards, London Irish wing Ollie Hassell-Collins did his England chances no harm with a well-taken try, while Chandler Cunningham-South also crossed for the Exiles.
Saracens managed two tries through Kapeli Pifeleti and Sean Maitland, with England's Owen Farrell kicking two penalties and two conversions.
But it was the boot of Paddy Jackson that ultimately proved the difference, the former Ireland fly-half landing five penalties, in addition to his two successful conversions, as the Exiles recorded just their third league win this season.
Despite the loss, Saracens remained 10 points clear at the top of the table.
Second-placed Sale looked on course to make inroads into Sarries' lead when they surged into a 14-0 half-time lead away to Newcastle.
But tries from Argentina star Mateo Carreras and Sam Stuart helped the Falcons complete a remarkable 20-14 comeback win, with Brett Connon kicking 10 points.
