Joe Clarke was part of the England Lions side which rewrote the record books in defeating Sri Lanka 'A' by 88 runs under the Duckworth-Lewis Method in the latest Tri-Series match at Northamptonshire's Wantage Road ground.
The Worcestershire batsman had only a bit part role after dropping down the order from four, where he had scored 37 in the win over Pakistan 'A' at Cheltenham, to six.
Clarke did not arrive at the wicket until the 46th over and made five from 10 deliveries.
The Lions totalled 393-5 in 50 overs – their highest score in List A cricket and beating the 378-6 versus South Africa 'A' at Mamelodi in 2014.
Skipper Dawid Malan smashed 185 not out from 126 balls with eight sixes and 16 fours, another record score for the Lions in List A cricket.
It surpassed the 168 by Ravi Bopara against West Indies 'A' at New Road in 2010.
Sri Lanka made 164-4 from30 overs before rain intervened.
The Lions players now return to their counties to play in tonight's round of NatWest T20 Blast fixtures before reassembling in Canterbury on Saturday ahead of the return matches against Pakistan 'A' on Sunday and Sri Lanka 'A' on Monday.
Four Worcestershire players were in England Under-19 action on day one of a two-day fixture against the Unicorns at Loughborough.
Ollie Westbury scored 21, Josh Dell ten, Ben Twohig nine and Josh Tongue five as the Under-19s were dismissed for 297 in 69.4 overs after electing to bat.
Tongue took the new ball and bowled five overs for seven runs as the Unicorns closed on 43-3 from 18 overs.