Man of the Match Andrew Flintoff smashes a boundary during his unbeaten innings of 52. (AP)

Nottingham, June 27: Andrew Flintoff's blistering unbeaten 50 set up an England victory against Sri Lanka in the opening match of the triangular one-day series here at Trent Bridge on Thursday.

Flintoff's 28-ball assault included two sixes and five fours, boosting England's total to 293 for seven.

He then followed that up with three for 49, including two in three balls, as England won by 44 runs.

Sri Lanka, despite a half-century from recalled keeper/batsman Romesh Kaluwitharana, finished on 249 for nine for after losing their last five wickets for 24 runs.

Naveed Nawaz was 15 not out and Dilhara Fernando five not out.

Earlier Flintoff found the ideal partner in veteran gloveman Alec Stewart, the Surrey stalwart making 83 and putting on 84 with the Lancashire all-rounder.

Sri Lanka's dashing top order was undone by some superb England catching which ably backed up an attack lacking injured spearheads Darren Gough and Andrew Caddick.

First captain Nasser Hussain took a breathtaking diving left-handed effort at extra-cover to dismiss opposite number Sanath Jayasuriya for 12 off paceman Matthew Hoggard.

But it took a while for 19 for one to become 91 for two as Kaluwitharana and Marvan Atapattu built a platform.

Atapattu had made 47 when he saw Essex captain Ronnie Irani, playing his first one-day international in over five years, dive forward at mid-off to give Flintoff a wicket.

Kaluwitharana and Mahela Jayawardene looked comfortable before Paul Collingwood's deceptively gentle medium-pace yielded two wickets in two overs.

First Kalu (52) was well-taken at short midwicket by Graham Thorpe before Collingwood clean bowled Jayawardene (29) to leave Sri Lanka 152 for four with 20 overs remaining.

Russel Arnold batted steadily for 29 but was unluckily run out following a deflection by bowler Hoggard.

And then Kumar Sangakkara (22) holed out to mid-on off Flintoff before in the same over Upul Chandana was caught close in by Thorpe.

Sri Lanka, now 215 for seven, had lost three wickets for three runs in six balls and with fewer than nine overs remaining the game was up.

Paceman James Kirtley, in his first one-day match since having his action cleared by the International Cricket Council, took two wickets in two balls before last man Fernando just survived the hat-trick.

In England's innings Collingwood finished 10 not out off three balls after Stewart had been bowled in the last over by Chaminda Vaas.

Sri Lanka, without star bowler Muttiah Muralitharan, looked to be containing England until Flintoff's arrival.

Fernando was the pick of the attack with two for 46 from eight overs.

But he could do nothing about a Flintoff onslaught which saw England add 87 runs in the final 10 overs.

India are the third team in this tournament and they start their campaign against England at Lord's on Saturday. (AFP)