Coventry beat champions Saracens 28-14 to record the big upset in the Premiership Rugby Cup's opening round.
A young Saracens side took a 10th-minute lead when Ben Harris went over, but Suva Ma'asi touched down from a lineout drive to level soon after.
Harris got a second after 37 minutes, but Will Wand made it 14-14 two minutes later as he went over under the posts.
Ryan Hutler scored early in the second half before Patrick Pellegrini's try in the final minute sealed the win.
Championship side Coventry became the first second-tier team to beat top-flight opposition in the newly revamped Premiership Rugby Cup, which sees all 12 second-tier sides taking on top-flight teams in competitive games for the first time in 18 years.
It is the first time Saracens have lost to a second-tier side since they were beaten by Cornish Pirates in 2021 in their first game after being relegated for financial issues.
In the only all-Premiership clash of the day, Henry Slade put his omission from the England World Cup squad behind him as he scored 21 points to help Exeter thrash Bristol 75-0.
A young Bristol side conceded 11 tries to a strong Chiefs line-up that included Wales centre Joe Hawkins and Australia prop Scott Sio.
Slade scored a first-half try and kicked eight conversions at Sandy Park.
In total, Saturday saw six Championship sides go up against Premiership opponents.
The closest to another upset came at Ampthill where the Bedfordshire side gave a good account of themselves before eventually losing 40-17 at home to Newcastle Falcons, after Josh Skelcey's 11th-minute try had given the Championship side a 7-0 lead.
The Premiership came back with six tries as Iwan Stephens went over twice in the second half.
Leicester ran in eight tries as they thrashed Caldy 50-6 at home as former London Irish winger Ollie Hassell-Collins found himself on the scoresheet.
Harlequins also scored eight tries in a 54-14 win over Hartpury at the Stoop thanks in part to 20-year-old Cassius Cleaves' hat-trick.
At Kingsholm, Gloucester could only muster six tries in their 42-14 win over Nottingham with Jack Clement scoring twice.
In the late match, Sale enjoyed a big win as Nye Thomas and Ethan Caine each scored two tries in a 47-12 win over Bedford Blues at the AJ Bell Stadium.