Alex Lewington’s hat-trick was not enough to prevent Saracens preserving their winning start to the season in dramatic fashion.
The London Irish wing crossed over three times at the Madejski Stadium, as the Exiles threatened to upset last season’s Aviva Premiership Rugby table toppers.
Blair Cowan had also scored for the hosts before the break but Tim Streather, Richard Wigglesworth and – in the dying stages – Billy Vunipola touched down to hand Sarries a third straight win of the season.
It was an end-to-end affair and Irish will be ruing four missed kicks at goal that would have sealed the victory.
Man-of-the-match Lewington scored three superb tries but the boots of Owen Farrell and Alex Goode ultimately proved the difference between the London sides.
Saracens started the game in blistering fashion, Streather going over in the right hand corner within 48 seconds after quick hands from both Vunipola and Farrell.
After a Farrell conversion and a subsequent penalty Irish then struck back, the Exiles exploiting the overlap with flanker Cowan, who has three caps for Scotland, going over unopposed in the corner.
Wigglesworth then sniped at the base of ruck and ran in to score through an absent Irish defence, with the Farrell conversion taking the score to 20-7.
But Irish hit back again with a sublime cross-field kick from Kiwi fly-half Chris Noakes finding Lewington on the right wing, who duly stepped inside past Chris Wyles and touched down for a brilliant try.
Lewington then closed the gap further to 19-20 as he gathered a perfectly-weighted grubber from Scott Steele and dived over to score.
Before the break Farrell added a cool 38-metre penalty before hitting the post with the final kick of the half, but the Exiles went ahead after the break with a penalty and Lewington’s third try.
The 22-year-old brilliantly evaded Wyles again on the right wing and scampered 30 metres to the line to complete a sensational hat-trick.
Goode kept Saracens in touch, slotting a simple penalty to take the scores level with 20 minutes to go but it looked like his side had thrown the game away with the full-back missing two kickable penalties.
But Shane Geraghty, having made a penalty from halfway, could not add to his tally, missing three long efforts that would have sealed the win.
Saracens never gave up and despite another penalty miss from Goode they had the last laugh.
Second-half substitute Charlie Hodgson opted to kick for touch with time running out. The catch and drive was set and Irish were powerless to avoid the inevitable as Vunipola bundled over in dramatic fashion.
Hodgson added the extras but the job was done, Irish having to settle for a pair of bonus points.