LONDON, Jan. 12 (Xinhua) -- World number one Ronnie O'Sullivan came back from 3-0 down to defeat Australian Neil Robertson 6-4 at the Wembley Masters Snooker here on Tuesday.

    The Aussie opened the match strongly by winning the first three frames in 78-1, 102-0, and 74-68. But the defending champion O'Sullivan fought back with a break of 114 in frame four and continued to edge his rival in the following three frames.

    Robertson, 27, blasted back with a 140 total clearance, the highest break of the tournament so far. But O'Sullivan wrapped up the last 16 match by winning two more frames.

    "It's hard to get excited. To make two or three centuries in a match is not a big deal, that's how the modern game is," said O'Sullivan, who finished the fourth centuries of the match with a break of 106 in the ninth frame.

    Frame three should be awarded as the most thrilling frame in the encounter as O'Sullivan led with the slightest advantage in 68-67 while Robertson faced the last ball on the table. After potting the black ball to earn seven points, Robertson celebrated with his right fist pumping the air.

    O'Sullivan said the celebration meant nothing to him. "I knew I was 3-0 down because of the mistakes I'd made."

    The 34-year-old O'Sullivan has won four times at the prestigious invitation event at Wembley and has a total of 22 titles in ranking tournaments. But the world number one believed that he played sub-standard shots a lot of the time. He even said that "the last time I played a good tournament was the (2003) European Open".

    O'Sullivan, dubbed the Rocket, is going to play against Peter Ebdon in the quarterfinals on Thursday.

    "My attitude will be the same in my next match. I won't be surprised if I win or lose," said O'Sullivan.