Ronnie O’Sullivan saved his best until last to clinch a final-frame decider against Liang Wenbo in the first round of the Dafabet Masters - but he admitted he thought he was heading home.

The Rocket hasn’t lost in the first round of the Masters since 2011, but his opponent was just a black ball away from knocking out the defending champion in the tenth frame on Sunday.

But O’Sullivan, who lives in Chigwell, survived and in the deciding frame hit 121, his highest break of the afternoon, to clinch his spot in the quarter-finals.

The Rocket will face Neil Robertson or Ali Carter in the next round on Thursday but felt Liang should have recorded his first Masters success.

“You have to feel for Liang, he’s had a good season, is playing well and should have really won that match, I don’t really know how I’m through to be honest with you,” O’Sullivan said.

“He should have put me away a little bit easier. I think I managed to nick a few through my experience, maybe that was the difference.

“I didn’t feel really good in myself, I feel like I’ve had a bug and a virus.

"I just felt really lethargic and tired and it was difficult to feel like I wanted to hold a cue let alone try and compete and win a match in the most highly competitive tournament we have.”

The six-time Masters champion took a 2-0 lead in the opening match of this year’s tournament but an impressive 109 break in frame three helped Liang to draw level by the mid-session interval.

O’Sullivan struck breaks of 89 and 80 to restore his two-frame advantage but again his Chinese opponent fought back and took the lead for the first time at 5-4.

And Liang had the perfect opportunity for the match in frame ten only for the 29-year-old to miss the final black into the corner pocket.

The Rocket made no mistake in the final frame with his first century break but knows he will need to improve dramatically in his next match on Thursday.

“I don’t think your B and C games can win you tournaments these days, it might win you the odd match like that,” he added.

“But if I play like that again in the next match I’m sure I’ll be sat next to Jimmy and Neal doing a bit of work on (Eurosport) punditry - we’ll just have to wait and see.”

Watch the London Masters LIVE on Eurosport 2, featuring daily studio analysis from Ronnie O’Sullivan, Jimmy White and Neal Foulds.