Match scores (SSE Swalec)
Surrey win by 8 wickets (D/L Method)
Glamorgan inns (48.3 overs): (Ingram 72, Rudolph 57; Dernbach 3-30, Curran 3-51)
Surrey inns (24 overs): 183-2 (Sangakkara 81 no, Stoneman 74)
Match report
The left-handed combination of Mark Stoneman and Kumar Sangakkara guided Surrey to a comfortable first Royal London One-Day Cup victory of the season on Sunday at the expense of Glamorgan.
Having restricted the hosts to 239 from 48.3 overs after opting to bowl first at the SSE SWALEC, the visitors easily chased down the amended target - under the Duckworth/Lewis method - of 182 in 29 overs.
Opener Stoneman hit 74 while Sangakkara finished unbeaten on 81 as Surrey cruised to 183 for two from just 24 overs.
Surrey captain Gareth Batty's decision to ask Glamorgan to bat first was immediately vindicated when Jade Dernbach trapped David Lloyd leg before wicket with the third ball of the innings, and in his second over knocked back Kiran Carlson's off stump to leave the home team seven for two.
Jacques Rudolph and Colin Ingram then resurrected the Glamorgan innings with some positive strokeplay, with Ingram striking Ravi Rampaul for one of the biggest sixes seen on the ground - a massive blow that landed some 150 yards away over backward square leg.
Rudolph, following on from the 121 he scored against Gloucestershire in the opening game, scored 57 from 65 balls, with nine fours, before he was bowled off the inside-edge by Sam Curran.
Ingram, who before the game was awarded his county cap, struck two other sixes and four fours in his 72, made from 96 balls, before he was caught on the long-on boundary attempting another maximum.
After the third-wicket pair had added 113 in 20.2 overs, Surrey's attack assumed control, with Dernbach rewarded for bowling a full length in his opening overs, then restricting Glamorgan's progress towards the end of the innings with his back-of-the-hand slower deliveries.
Batty also bowled a miserly spell, with figures of 10-1-36-1, and, with Glamorgan's late-order batsmen finding various ways of getting out - including caught off the back of the bat and a comical run-out - the home team were dismissed for 239 with nine balls of their innings remaining.
Surrey's reply did not get off to the best start when Dominic Sibley was dismissed in the fourth over, but the second-wicket pair of Stoneman and Sangakkara put on 125 in rapid time.
Stoneman produced his 74 from 48 balls, with 56 runs coming from boundaries, and, after he departed, Rory Burns joined Sangakkara in the middle.
The Glamorgan bowlers struggled with a wet ball, as the sparse crowd were treated to a masterclass from the Sri Lankan batsman.
Sangakkara finished 81 not out with 11 fours as Surrey won with five overs remaining.