O'Sullivan gave Maguire few chances

Resuming with a 5-3 lead, he reeled off four straight frames to book a clash with Stephen Hendry or Mark Williams.

John Higgins cruised through after completing a 9-2 win over Stephen Lee and was joined in the last eight by Graeme Dott, who beat Robin Hull 9-1.

Peter Ebdon sealed his spot in the last eight by beating Stuart Bingham 9-4.

Fifth seed and former world champion O'Sullivan was not entirely happy with his form despite his comfortable win over Maguire.

I'm playing within myself and there is more to come World champion Graeme Dott

"Stephen made a few mistakes that allowed me to get in, but relying on people to do that is not the ideal way to win matches." he said.

"I like to create my own chances to win frames but I suppose I managed to score when I got in."

Reigning world champion Dott, who will meet Steve Davis or Alan McManus next, was more satisfied with his display.

"I didn't score quite as heavily against Robin as I did in my first match but still played quite well," said the Glaswegian.

"I feel I'm playing within myself and there is more to come. I'm hitting the ball really well.

"People say I'm dogged and determined, which is right. But now I'm showing a different side, showing I can play as well."

Provisional world number one Ken Doherty and defending champion Ding Junhui edged ahead in their matches.

Doherty opened a 5-3 advantage over Joe Perry in their first session, while Ding led by the same scoreline against 2003 champion Matthew Stevens.

The Chinese teenager made breaks of 111, 100 and 92 before the interval but the Welshman kept himself in touch by compiling runs of 82, 74 and 66 after the break.