Shaun Udal and Murali Karthik tore through Somerset's batting line-up to guide Twenty20 champions Middlesex to a 43-run Pro40 victory at Lord's.

Somerset, set 204 to win, saw Marcus Trescothick race to 40 off 35 balls before falling to Tyron Henderson.

The opener's dismissal sparked a batting collapse as Udal (3-21) and Karthik (2-36) constricted the runs.

Owais Shah shone with the bat for Middlesex with 96, ably assisted by Henderson's 50 off just 25 balls.

Shah, omitted from England's 13-man squad for the fourth Test against South Africa starting at The Oval on Thursday, played a mature innings just when his team required a big performance.

Seamer Charl Willoughby tore through Middlesex's top order, claiming three wickets as Middlesex were reduced to 50-5.

But Shah's mature innings was brutally complemented by Henderson, who bludgeoned six boundaries and two sixes during his stay at the crease.

Shah continued the onslaught after Henderson's dismissal, taking Middlesex past the 200 mark with a flurry of boundaries but just missing out on three figures.

Stout hitting from Trescothick ensured the response began with a bang, but his dismissal sparked a six-wicket collapse for just 31 runs as Somerset struggled to 103-7.

Once again Middlesex were indebted to Udal and Karthik, the chief architects in the Twenty20 Cup success at the Rose Bowl two weeks ago.

The pair bamboozled Somerset's middle order with their variations and flight, conceding just 57 runs from their 16 overs.

An eighth-wicket stand of 45 between Omari Banks and Ben Phillips briefly raised Somerset hopes.

But any lingering thoughts of victory ended when Dirk Nannes had Banks caught by Shah for 29 before a smart stumping from Ben Scott removed Phillips for 17.