Surrey were left still looking for their first win in any competition as Gloucestershire completed a 42-run totesport League victory at Bristol.
Alex Gidman top scored with 70 and Philip Weston hit 53 as the Gladiators ran up 257 for six after winning the toss.
Surrey used eight bowlers, Tim Murtagh taking two for 48 from nine overs and Adam Hollioake two for 26 from four.
Mark Ramprakash (73) and Ricky Clarke (41) seemed to have the Lions on course when 125 were needed off the last 20 overs with eight wickets in hand.
But Chris Taylor's three run-outs and two catches proved significant as they wilted to 215 for nine.
It was Gloucestershire's first win of the season in the totesport League at the third attempt and added to Surrey's alarming slump this season. Shoaib Malik was the pick of the bowlers with two for 39 from his nine overs.
Earlier, Weston and Craig Spearman had given Gloucestershire a bright start in the sunshine with an opening stand of 54 in ten overs.
Left-hander Weston played some glorious shots to strike seven boundaries in helping the score to 111 and the base was there for a big total.
The home side never really accelerated, despite Gidman's 89-ball innings, which featured five fours, and a solid 46 from Matt Windows. In the conditions 257 appeared no more than a par total.
It certainly looked that way as Ramprakash and Clarke set about building Surrey's reply from a disappointing start of 36 for two. They put together a century stand off 109 balls and Gloucestershire were struggling on the back foot.
Then Clarke fell lbw to Mark Alleyne and Ramprakash tried one sweep shot too many against off-spinner Shoaib, moving across too far and being bowled behind his legs.
The total was then on 163 for four and 95 were needed off 81 balls.
But, apart from Hollioake who made 33, the rest of the Surrey batting was a shambles as Gloucestershire backed up their bowlers with excellent fielding.
Taylor could do no wrong. The ball seemed to follow him around as, having run out Scott Newman early on, he did the same to Hollioake and Jonathan Batty, who had been lucky to survive an earlier run out when umpire Alan Whitehead did not consult the TV replay.
* Mark Ealham smashed 40 runs off 20 balls and then took two vital wickets as Nottinghamshire Outlaws toppled totesport League Division Two leaders Leicestershire Foxes by 43 runs at Grace Road.
Chasing 253 for victory, the Foxes were dismissed for 209 to slump to their first defeat of the season in the competition.
The victory was due in no small measure to former England all-rounder Ealham, who provided some real fireworks to lift the Nottinghamshire total to 252 for five.
Ealham and Chris Read shared a sixth-wicket stand of 59 in six overs. Ealham hit two fours and four sixes in a blistering assault on the home attack with 33 runs coming off the last two overs from Mark Cleary and Darren Maddy.
Read scored 32 off 40 balls as the Outlaws innings suddenly took off after a sedate start, despite a patient 68 from opener Jason Gallian.
At 198 for five off 40 overs the Foxes would have hoped to keep the Notts total well below the 250 mark, but Ealham's blitz totally transformed the innings.
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