Saracens (8) 21
Tries: Skirving, penalty Con: Jackson Pens: Jackson 3
Gloucester (13) 25
Tries: Allen, Morgan, Vainikolo Cons: Lamb 2 Pens: Lamb 2
Gloucester's Anthony Allen scored on his first appearance since the opening day of the season as Saracens suffered their first home league loss this term.
Both sides had penalties on the board when Allen claimed the first try, with Ben Skirving replying for Saracens.
Olly Morgan and Lesley Vainikolo then went over before a penalty try for Saracens closed the gap.
But despite the home side laying siege to the Gloucester line, they could not find a way to cut the deficit further.
Welsh international Gareth Cooper was an unused replacement for Gloucester, despite being caught up in the on-going row over player availability during the international window.
He played for Wales against South Africa last weekend and will report back to the Wales squad on Monday for next Saturday's game against New Zealand, having been released from the squad for Friday's win over Canada.
But Gloucester named him on the bench for this game, despite being warned they were breaking International Rugby Board rules by doing so.
"It is an issue for Premier Rugby, the Welsh Rugby Union and the Rugby Football Union to resolve," coach Dean Ryan told BBC Radio Gloucester.
"The decision was taken in conjunction with Premier Rugby that Gareth would be part of our 22 - and he was. "
Saracens director of rugby Eddie Jones:
"The scrum is a difficult area of the game to manage but today we dominated it without getting the reward we were due.
"I just feel that if people are penalised for persistent fouls in other areas of the game then the same should be true of the scrum.
"Ultimately it's about consistency and I didn't feel we get that at the moment with one of our strongest areas."
Gloucester head coach Dean Ryan:
"We've played very well today and I felt like we were back to the Gloucester of old.
"Olly Morgan has taken his try extremely well and Anthony Allen slotted straight back in.
"He is a player who knows the Gloucester way and we haven't played that way until today, even when we won, so I'm very happy to be back to that."
Saracens: Goode, Sorrell, Powell, A. Farrell, Cato, Jackson, de Kock, Lloyd, Cairns, Visagie, Chesney, Vyvyan, Skirving, Saull, Owen.
Replacements: Barritt for A. Farrell (51), Mercey for Visagie (70), Ryder for Chesney (54), van Heerden for Skirving (54).
Not Used: Kyriacou, Wilson, Thrower.
Sin Bin: Vyvyan (17).
Gloucester: Morgan, Balshaw, Tindall, Allen, Vainikolo, Lamb, Lewis, Wood, Azam, Forster, James, Brown, Buxton, Satala, Strokosch.
Replacements: Barkley for Allen (63), Eustace for James (58).
Not Used: S. Lawson, Young, Titterrell, Cooper, Watkins.
Ref: Sean Davey (RFU).