Northern Ireland's Allen became the highest profile casualty of the event so far as the fourth seed lost 10-8 to Wales' Jamie Clarke.

Allen was in blistering form in the first session of the match registering four centuries, and winning a fifth frame on a respotted black to take a 5-4 advantage into the evening's play.

However, the world number 89, making his debut at the sport's blue riband event, fought back impressively against an out-of-sorts Allen to secure a place in the second round.

Another seed to suffer a surprise defeat today was England's Shaun Murphy, the 2005 world champion who is seeded ten this year.

Murphy, who went into today's second session trailing 6-3 to Noppon Saengkham, lost 10-4 to this Thai opponent, as the world number 42 claimed one of the biggest wins of his career.

There was better news for the seventh seed, England's Mark Selby, as the three-time world champion battled to victory against Northern Ireland's Jordan Brown 10-6.

Resuming 5-4 from yesterday's opening session, the pair split the first four frames of the session giving Selby a 7-6 lead.

The Englishman then won three frames in a row to clinch a hard-fought win and a place in round two.

In the day's other matches England's Martin Gould leads the ninth seed, Scotland's Stephen Maguire 7-2, while England's Barry Hawkins, the 15th seed, leads Alexander Ursenbacher of Switzerland by the same scoreline - 7-2.

Those two matches conclude tomorrow which in turn completes the first round of the tournament.

Two second round matches, played over the best of 25 frames and three sessions, get underway tomorrow with Scotland's John Higgins, the fifth seed, playing Norway's Kurt Maflin and two former world champions doing battle as Wales' Mark Williams faces England's Stuart Bingham.

World Snooker today announced that artificial crowd noise, which it has trialled within the arena after the tournament was moved behind closed doors following the first day's play, would remain for the rest of the event.

The decision was taken following feedback from broadcasters, players and fans, with the artificial noise being used for player entrances, centuries, outstanding shots and at the end of frames and matches.