Sussex 400 for 4 (Alsop 189*, Pujara 132) beat Middlesex 243 (Cracknell 71, Crocombe 3-33, Rawlins 3-61) by 157 runs

Sussex secured a home semi-final in the Royal London One-Day Cup after their rampant batsmen made 400 for four against Middlesex at Hove, hitting 249 from their last 20 overs.

They were led by an unbeaten 189 not out by Tom Alsop, his best List A score, while captain Cheteshwar Pujara continued his spectacular form with 132, the pair adding 240 for the third wicket in 27 overs as Sussex topped Group A with six wins in eight matches. With results going against them elsewhere, Middlesex were knocked out of the competition.

The Sussex total was their highest score in one-day cricket, beating their 399 in a 40-over game in Horsham. They scored 397 for five against Somerset at Taunton on Friday.

Long before they were finished, they had passed their previous one-day best against Middlesex, 333 for four at Hove last year. It was also the highest one-day score against Middlesex, beating Nottinghamshire's 368 for two at Lord's in the same competition in 2014.

That left Middlesex needing to beat their previous best chase (292 for four against Surrey at Lord's in 2014) by a big margin. Essentially, Middlesex were required to play Twenty20 cricket for 50 overs. And, with their deep batting, they kept coming at the Sussex bowlers even as the wickets tumbled. Joe Cracknell led the way with a 73-ball 71, with ten fours and there were plenty of bright cameos but the task was overwhelming and they were bowled out for 243 in 38.1 overs.

When Sussex started their innings, they looked unlikely to scale the heights. Invited to bat in damp conditions, under floodlights and heavy clouds, they must have suspected the odds were against them, even though the depleted Middlesex attack was missing the injured Umesh Yadav, Toby Greatwood and Ethan Bamber.

Alsop, back from a back spasm and replacing Dan Ibrahim, and Ali Orr, in subdued form after his double century at Taunton, looked sedate rather than commanding as they took 58 runs off the opening ten overs.

Orr fell for 20 off 28 deliveries, caught behind as he played a diffident stroke against the impressive Thilan Walallawita, and it was 95 for two in the 18th over when Tom Clark chopped on a wide one from Max Harris.

Alsop and Pujara then put on 240 for the third wicket in 27 overs. Pujara started methodically, as he always does, and reached his half-century from 49 deliveries; he then doubled his strike rate, scoring 82 more from another 41, finishing with 20 fours and two sixes in his third century in the competition.

After 32 overs Sussex were 160 for two, scoring at exactly five an over. They added 240 runs in their final 18 overs. The spinners Walallawita and Luke Hollman - early on - put a brake on the Sussex scoring. But Middlesex's success with their slower bowlers ended when Stoneman's three overs went for 33 and both Alsop and Pujara got after Martin Andersson, who conceded 110 in his nine overs, and Harris, who went from 90 in ten.