Aiden Markram impressed with both bat and ball as champions Hampshire made it three wins from as many One-Day Cup matches this season with a 119-run rout of Middlesex on Tuesday.
South African opener Markram, who is warming up for the World Cup in England later this season, made 88 off just 90 balls in a total of 301 for nine before his part-time off-spin yielded figures of three for 39.
Liam Dawson (three for 37) and former Proteas fast bowler Kyle Abbott (three for 36) were also in the wickets as Hampshire won with 80 balls to spare at Southampton.
Victory, following previous wins over Kent and Glamorgan, saw Hampshire top the South Group.
England one-day captain Eoin Morgan was dropped twice on the boundary by Rilee Rossouw, both difficult chances, on his way to top-scoring for Middlesex with 41.
But his innings ended when he found Abbott at short fine leg off Markram.