BANGKOK, March 9: World champion Ronnie O’Sullivan and world No 1 Mark Williams set up an enticing semifinal clash of the Thailand Masters after the two in-form players won their quarterfinals in contrasting style Friday.

Williams dumped Irishman Fergal O’Brien 5-1 while O’Sullivan overcame seven-times world champion Stephen Hendry 5-3.

O’Sullivan, one of the few players to have a winning head-to-head record against Hendry over a long series of matches, stretched his advantage to 18-15 with another fine performance.

Hendry edged ahead by taking the first frame, but O’Sullivan hit back by bagging the second and third with breaks of 59 and 71. The 33-year-old Scot levelled at 2-2 with a position-perfect clearance to the pink of 122, the 556th century break of his illustrious 17-year professional career.

Hendry, however, failed to maintain his rhythm after the interval. He missed a red leading 35-0 in the fifth and paid the penalty as O’Sullivan replied with 63 before sealing the frame on the final red. Then in frame six, he narrowly failed with an attempted double into a centre pocket and O’Sullivan made 72.

A break of 54 cut the deficit to 4-3 but Hendry squandered two good chances in the eighth frame and O’Sullivan closed the match out with a 75.

Looking ahead to his match with Williams a repeat of their UK Championship semifinal which he won 9-6.

Williams had little trouble in seeing off Dubliner O’Brien 5-1 to book his place in the last four.

Matthew Stevens reached his first semifinal of the season by beating an out-of-sorts John Higgins 5-3 and will meet Stephen Lee, who overcame defending champion Ken Dohery 5-4.