Saracens hooker Schalk Brits was influential in the loose for the hosts
Four penalties from teenage Saracens fly-half Owen Farrell ensured victory over Gloucester and a second successive Premiership final against Leicester.
Farrell, 19, landed two kicks before half-time, answered by one from Nicky Robinson, in an error-strewn match dominated by rugged defending.
Saracens skipper Steve Borthwick was harshly sin-binned after the break for an offence at a line-out.
Robinson then scored the only try but Farrell's kicking proved too much.
The game was littered with mistakes from the start when Robinson's kick-off went straight out.
Both sides knocked on, players lost their footing and there were eight missed penalties in the blustery conditions - six of them from Saracens who tried three kickers before settling on Farrell.
All the errors, coupled with some well-drilled defending on both sides, stalled the game's momentum and made for a poor spectacle at times.
Things had started brightly when James Short appeared to have scored with five minutes gone but the video replay showed Rory Lawson's desperate tackle on the Saracens winger had just put him in touch in the corner.
Farrell put Saracens ahead on 16 minutes and made it 6-0 after a loose Sarries line-out saw Schalk Brits dance his way into the Gloucester 22 and the visitors infringed at the breakdown.
Brendan Venter sought out Farrell for special praise
The hosts looked like their forwards might power over on the half hour but their tight drives came to nothing when the ball was stripped by Eliota Fuimaono-Sapolu within yards of the line.
Cherry and Whites saved their best attacking phase until the final minute of the half when, following a Robinson break up the middle, they put together 12 phases in the face of belligerent tackling and won a penalty that Gloucester's number 10 converted with the last act of the period.
Farrell extended his side's lead to 9-3 at the start of the second half but Robinson's chance to bring Gloucester back within three points moments later sailed wide.
The error count continued to rise as first both scrum-halves kicked the ball out on the full and then Ernst Joubert's break into Gloucester's 22 was knocked on by substitute Neil de Kock before Gloucester's counter-attack saw James Simpson-Daniel run out of room.
Borthwick was yellow-carded on 63 minutes when he appeared to take Alex Brown out in mid-air at a line-out but replays indicated the decision was highly questionable.
The officials then missed a genuine offence minutes later when Jacques Burger hit Gloucester full-back Freddie Burns with a very late tackle.
Saracens, stung by losing their captain, stepped up their efforts and pressed for a killer blow.
After the pack twice came close to making a breakthrough, Farrell lined up for the drop-goal but his attempt was charged down and Robinson, Burns and Simpson-Daniel combined to put the Welshman away.
Robinson grounded the ball under the posts and added the extras to give Gloucester the lead, at 10-9, for the first time with 10 minutes to go.
But with three minutes on the clock referee Andrew Small made another big call when he awarded the home side a penalty when it appeared they had knocked on at a ruck.
Farrell, under the gaze of his father Andy who brought on the kicking tee, held his nerve to hand his club a chance at avenging
last year's defeat in the final.
Saracens director of rugby Mark McCall:
"It says everything about Owen Farrell that he missed a couple of kicks at goal and he is the guy who wants to put his hand up to kick the winning penalty.
"He has been incredible for us over a six-month period. He has guided the team to this run of victories we have had and he did that again today.
"We felt we were in control in the first half but it wasn't evident on the scoreboard. We left some chances out there. It was tight and nervy.
"Everybody knows the touch-judge made a big error [over Borthwick].
"We expect better at this level in these kind of games, it could have been a match-changing error for us to go down to 14 men with 16 minutes to go.
"They scored their try and it could have been match-changing. I am pleased our boys had the resolve to come back and seal the victory."
Gloucester head coach Bryan Repath told BBC Gloucestershire: "In big games like this you need to do your basics well, and in tight games you need that 5% to go your way.
"In the first half we never got into any kind of rhythm. Credit to Saracens, they were defensively pretty hot all day.
"We went in at 6-3 and we had our opportunities in that time. We have matured a lot. We competed and made them fight hard for every point and among the players there are a lot of disappointed people.
"It's been a strong season and hopefully the start of a new challenge for a lot of the players. Some will get opportunities next season. It's hard to look at it and be upbeat after losing a semi-final but we've got a trophy (LV Cup) and we got into the play-offs and I can't really ask for much more. The players deserve a lot of credit."
Replacements: Cato for Short (51), de Kock for Wigglesworth (59), Du Plessis for Nieto (70), Vyvyan for Botha (50), Saull for K. Brown (62).
Sin Bin: Borthwick (63).
Gloucester: Burns, Sharples, Molenaar, Fuimaono-Sapolu, Simpson-Daniel, Robinson, R. Lawson, Wood, S. Lawson, Doran-Jones, Hamilton, Brown, Strokosch, Qera, Narraway.
Replacements: Voyce for Burns (76), Trinder for Molenaar (65), Lewis for R. Lawson (62), Dickinson for Wood (67), Dawidiuk for S. Lawson (76), Harden for Doran-Jones (74), Attwood for Hamilton (51), Deacon for Qera (70).
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