WALES' big three – Mark Williams, Matthew Stevens and Ryan Day – are all in action at the Newport Centre today.

Gwent star Williams takes on Stoke's Jamie Cope at 1pm and with Stevens facing Day from 2pm at least one home favourite is certain of a spot in the quarter-finals.

Day will be on a high after following up Monday's 4-0 whitewash of Jimmy White with a 4-2 victory over Ronnie O'Sullivan last night.

It was the Pontycymer potter's first ever win against the Rocket, at the fifth attempt.

Day capitalised on a miss from O'Sullivan in frame one to clear the table with a confident 109. The second frame started in similar fashion for the 30-year-old from Bridgend as he cleared the table once again with a fantastic break of 113.

The Rocket responded in frame three and produced a master class of his own with a break of 100. However, Day took the fourth when O'Sullivan struggled to get out of a tricky snooker and conceded 24 points to his opponent.

O'Sullivan did manage to take the fifth frame with a top break of 56 to make it 3-2. The sixth could have gone either way but after O'Sullivan missed the pink with one red left, his chance was gone as Day cleared for a famous victory.

"To beat Ronnie is one of my best victories for sure," said the World No 24. "I'm looking forward to playing my good friend Matthew in the next round, it's a pity we could not have met in the final, but that's just the way it has to be."

O'Sullivan said: "Every credit to Ryan, he played well and deserved it."

Also last night Mark Selby booked a quarter-final place with a hard-fought 4-2 success over Mark King.