Ravi Bopara and James Taylor both hit centuries as England Lions thrashed Sri Lanka A by seven wickets at New Road.
Bopara scored 106 while Taylor finished up unbeaten on 103 as the hosts chased down their opponents' total of 283-6 with 21 balls remaining.
England will now face New Zealand 'A' at the same venue on Tuesday to decide the winners of the Royal London One-Day Series.
Earlier, Steven Finn had given his hopes of a Test recall a boost with four wickets, including the scalps of both Sri Lanka's openers within the first 10 overs.
England won the toss and chose to field, which looked a wise decision when Finn dismissed Mahela Udawatte (four) in the third over and then Danushka Gunathilaka (nine) in the seventh.
Dinesh Chandimal entered the crease with the score on 16-2 but the 24-year-old hauled his team back into contention with a superb unbeaten 119 in 127 balls. He was ably supported by Ashan Priyanjan, who made 42 before being caught behind off Bopara (1-29).
Bhanuka Rajapaksa (46) played a sensible innings too, but he fell just short of his half century when he was caught by James Vince off the bowling of Somerset's Craig Overton (1-60).
Chaturanga de Silva (21) and Seekkuge Prasanna (26) added some late runs down the order but both were dismissed by Finn as Sri Lanka closed on 283-6 after 50 overs.
England's response got off to a solid start thanks to Vince (32) and Alex Hales (24), but both fell in quick succession to Prasanna (3-42).
At 66-2 Sri Lanka were on top, only for Bopara and Taylor to combine to steer the contest away from their opponents with a superb stand of 194 that put England right back on course for victory.
Essex all-rounder Bopara was eventually stumped by Chandimal off Prasanna but the game was already won and it was left to Taylor and Jason Roy (12 not out) to see the home side over the finishing line.