Scottish fly-half Gordon Ross also made Gloucester pay for errors in front of their own posts by booting unmissable penalties.

But a try had to come and it arrived through a brilliant break by Ross, a lay-off to full-back Dan Scarborough and a slight of hand inside to centre Adam Powell who plunged over.

Ross converted and added another penalty before his team were robbed of a certain try when Francisco Leonelli's pass to blood replacement Edd Thrower, with the line beckoning, was ruled forward.

Flanker Andy Hazell did Gloucester no favours either by being sin-binned for a late tackle on Sarries skipper Neil De Kock.

Saracens were walking it until young Gloucester fly-half Ryan Lamb turned the game on its head with his boot and his running game.

A couple of Lamb penalties preceded a well-worked try down the right for England centre Anthony Allen that the 21-year-old converted.

And another penalty sent Gloucester into the interval with a 19-14 lead that few in the crowd could really believe.

However, Saracens returned with new gusto and soon crossed the line again as Leonelli cut past tacklers on the opposition 22 before laying off a neat pass for centre Kevin Sorrell to score and Ross to convert.

But Ross was the culprit as he threw out a pass inside the visiting 22 to lock Hugh Vyvyan only for Lamb to intercept and race 90 yards under the posts, converting it himself.

Gloucester number eight Luke Narraway added another try before Saracens replacement Thrower cut his team's deficit with a third touchdown of the game.

Yet, Gloucester restored their advantage and secured a bonus point with a fourth try in the corner by replacement full-back Olly Morgan after good work by another replacement, fly-half Willie Walker, Mike Prendergast and ex-Leicester back Leon Lloyd.

And Saracens settled for a losing bonus point at the end with Ross kicking a fourth penalty of the afternoon as Gloucester closed the game out.