London Irish turned on the second-half afterburners at Twickenham to complete a 33-16 bonus-point victory and put an early dent in Saracens' Aviva Premiership Rugby title hopes on Saturday.
The Exiles capitalised on the sin-binning of Alex Goode by amassing 15 points, including tries for Delon Armitage and Sailosi Tagicakibau. Ryan Lamb, who had kicked two penalties in the first half, landed another five points to give Irish a 21-10 lead with 15 minutes to go.
Goode was a key performer during Saracens' march to the Premiership final last season, but his conversion to fly-half today could only be deemed a failure. Apart from the yellow card that ultimately proved decisive, he made a series of minor errors and was restored to full-back midway through the second half before being hauled off altogether.
Impressive tries from Ernst Joubert and Schalk Brits saw Saracens control the first half, which they finished 10-6 up, but Irish's play after the interval was clinical. A penalty try that earned substitute Kevin Barrett a yellow card - the fourth of the match - and a late touch down from Topsy Ojo completed the rout in the final 10 minutes.
It was Irish who came out on top during a bruising opening 10 minutes, though their ambitious decision to opt for a scrum and line out at two penalties failed to pay off.
Saracens won a crucial turnover at a scrum five metres from their line and then watched as Lamb horribly skewed a long-range penalty attempt. Brad Barritt and Chris Wyles made breaks to put Saracens on to the front foot but both defences had tightened and there was less space to exploit.
It was going to take something special to breach the whitewash and it was delivered by Saracens in the 25th minute. A brilliant offload from hooker Brits found Wyles who dashed forward before slipping a pass behind his back to Joubert and the South African cantered over.
Irish responded with a penalty from Lamb but in the 34th minute Saracens powered over for a second try with Joubert the creator on this occasion. The number eight broke from the back of the scrum, Richard Wigglesworth probed at the ensuing breakdown before the ball was released to Brits who crossed from five yards out.
Another penalty from Lamp kept Irish in touch - Goode had missed both conversions - and by half-time they trailed 10-6.
A brisk start to the second half that saw winger Tagicakibau brought down just short of the line paid dividends, however. Lamb attacked the gainline and Goode palmed his pass to safety from an offside position, resulting in a yellow card and another three points for the Exiles fly-half.
Irish continued to press and were rewarded with their first try when a missed pass from Steffon Armitage found brother and man of the match Delon who sped over. Saracens were paying a high price for Goode's sin-binning and just three minutes later they slipped further behind when Steffon Armitage stole an up and under and the ball was recycled to Lamb.
Spotting a vast overlap on the left, Lamb launched a crossfield bomb that Tagicakibau collected before completing the easy run-in with the former Gloucester fly-half also converting.
Irish saw Paul Hodgson sin-binned for a deliberate knock-on of a pass by Barritt and substitute Derick Hougaard gave Saracens hope with two penalties. But despite Hodgson's absence the Exiles still managed to breach the whitewash.
Ojo duelled with Barrett during a run to the line, first being illegally pulled back by the Saracens substitute and then being shoved over as he was about to dive on the ball over the line.
Referee Andrew Small justifiably awarded a penalty try and Barrett was sin-binned, before Ojo crossed in the dying seconds with Saracens' defence in pieces to wrap up victory.