Brad Barritt's late try proved to be the difference maker as Saracens clawed their way back from a 17-9 deficit with only 16 minutes to go.
Gloucester will kick themselves as their own ill discipline cost them dear in the final quarter as they tried to close out the game but Saracens showed the class of champions in the way they dragged victory out of the jaws of defeat.
Until those final few minutes, Gloucester looked set to claim the win with a performance based on guts and commitment and Olly Morgan's superb first half try.
But they couldn't quite kill off the Men in Black and Owen Farrell enhanced an already impressive reputation by taking over kicking duties and then carving out Barritt's try scoring opportunity.
Credit to both sides for the monumental tussle but Gloucester will rue the unnecessary penalties that allowed their opponents back into the game.
There was obviously a lot riding on this game and the tension showed as a brawl kicked off with only 45 second the clock, referee Wigglesworth delivering a lengthy lecture to both teams.
The opening exchanges saw different tactics employed. Saracens quickly launched a couple of high bombs whereas Gloucester were trying to keep the ball in hand and look for space in the wide channels.
And they so nearly exploited the space on 8 minutes as Jonny May came in off his wing from a pre called move to cut through the Saracens midfield but Morgan just couldn't find the scoring pass to Sharples.
Kingsholm was literally buzzing as a couple of marginal calls went against Gloucester and a late hit from Owen Farrell on Henry Trinder enraged the locals.
A penalty was awarded, however, and Freddie Burns made no mistake from distance to give his side a 3-0 lead after 15 minutes.
The home pack were also acquitting themselves well at scrum time but won a second penalty for good work at the ruck. Again Burns went for the posts from near half way but the kick just faded wide right of the posts.
The visitors started to work their way back into the game but then Gloucester scored an absolute cracker.
Olly Morgan gathered a high kick just outside his 22, sidestepped a man and set off downfield. Henry Trinder carried the move on before passing back inside to Morgan who took a great angle to score in the corner. Burns couldn't land the tricky conversion but Gloucester led 8-0 on 24 minutes.
The breathless nature of the first half continued and Gloucester continued to pummel Saracens at scrum time but the visitors had the next chance of points as Will James was ruled to have tackled Schalk Brits high. Charlie Hodgson got his team on the board with the penalty. 8-3 after 36 minutes.
However, Burns promptly restored the eight point advantage as the visitors came up offside and then kicked the ball away to concede ten metres and make the kick even easier. Kingsholm roared its approval.
Time was up on the clock but Gloucester slipped the bind at the final scrum and Hodgson attempted the penalty from inside his own half but was well short and wide.
The first half had flown by with barely a break in play and it had been good value for the home supporters.
Gloucester were worthy of the lead having played with a passion and commitment that had visibly rocked the visitors. There was obviously much more to come from Saracens but Bryan Redpath's side could take great heart from the first half performance.
Saracens though had a chance to get off to a flyer as Gloucester dropped the kick off and then conceded a more than kickable penalty only for Hodgson to drag it left of the uprights.
Saracens though given another opportunity moments later as Gloucester were ruled to have pulled down a maul. Owen Farrell took over kicking duties and made no mistake. 11-6 after 47 minutes.
Freddie Burns then lifted the stadium as he showed real vision to jink his way through traffic and chip over the last man only for Alex Goode to get across and hack into touch to save the day.
Gloucester looked for the catch and drive but another fight broke out and Nick Wood and Rhys Gill both saw yellow after trading blows under the nose of the assistant referee and the chance was gone.
And nerves really began to jangle as Gloucester were twice penalised at scrum time and Owen Farrell sneaked the penalty home to narrow the gap to 11-9.
There was an immediate response though as Saracens were twice caught offside and Tim Taylor, who had by now replaced Freddie Burns, slotted the penalty.
The game entered its final quarter and Gloucester had to reshuffle their backs as Jonny May left with an arm injury. Taylor and Tindall were already on so Dave Lewis had to go on to the left wing.
But it was the pack who again stepped up to the plate and won another penalty at scrum time. Taylor again did the rest for 17-9 after 64 minutes.
Saracens were far from done. Neil de Kock made a sniping break around a ruck and it was just enough to make a crucial few metres. Gloucester didn't release the tackled player and Farrell made it 17-12 with eight minutes to play.
The pressure mounted and Gloucester gifted Saracens dream field position as Rory Lawson dropped a high kick and Dave Lewis picked it up in an offside position.
The visitors went for the corner but then Farrell dribbled a delightful kick in under the posts and Brad Barritt won the fight to score. Farrell converted for give Saracens the lead.
Gloucester, sensing a rare home defeat, mounted a last ditch assault on the Saracens 22 and the Kingsholm faithful howled in dismay at what looked like an obvious offside was missed by the officials.
A knock ended effectively ended the game as Saracens kicked their ball dead and kicked off their own enthusiastic celebrations.
|Gloucester Rugby Score Card|
|Saracens Score Card|