Masters 2017: Ronnie O'Sullivan beats Liang Wenbo in first-round thriller
|Dafabet Masters 2017|
|Venue: Alexandra Palace, London Dates: 15-22 January|
|Coverage: Watch live on BBC TV, Connected TV, Red Button, BBC Sport website and app.|
Defending champion Ronnie O'Sullivan reached the Masters quarter-finals with a 6-5 win over Liang Wenbo after coming perilously close to a shock defeat.
The Chinese world number 11 fought from 4-2 down to lead 5-4 - before missing the final black in the 10th frame that would have given him victory.
England's O'Sullivan, 41, seeking a record seventh Masters title, made 121 in the deciding frame to seal the win.
He will play either Neil Robertson or Ali Carter in the last eight.
In the day's other first-round match, 2011 winner Ding Junhui defeated English world number 16 Kyren Wilson 6-3 to advance.
The Chinese world number six, who had not won a Masters match in five years, was close to a maximum in the second frame before breaking down at 120.
Ding produced a break of 50 in the ninth frame, which - coupled with a mistake from 25-year-old Wilson when he sank the white - was enough to see him over the line.
He will now face either former world champion Stuart Bingham or Joe Perry.
Earlier, O'Sullivan told the BBC he felt ill during his tussle with Liang.
"I didn't deserve to win - I was there for the taking," said the former world number one. "I feel for him because I know what that feels like.
"When Liang was on that final black I thought I'd have a nice week off. I wasn't feeling well today and I was tired. I've had it for about a month."
O'Sullivan looked set for defeat in the 10th frame when he failed to pot the pink into the right centre. That allowed Liang to clean up to the final black, which he subsequently missed into the left corner.
The five-time world champion then notched up a brilliant ton in the 11th and final frame to the delight of his supporters inside Alexandra Palace in London.
Asked about his 121 break, O'Sullivan said: "I didn't feel any adrenaline in the final frame. I didn't feel like I was in the match. I just hung in there and tried to stay professional."
O'Sullivan is ranked 13 in the world and won only one ranking title last season. He did, however, reach the final of the UK Championship in December, where he was defeated by world number one Mark Selby.
He is level with Stephen Hendry in terms of the number of titles at the Masters - but did not seem concerned about breaking the record this year.
"I'll have another chance," he said. "I don't see much grassroots coming through. I can play until I'm 50."
Sign up to My Sport to follow snooker news and reports on the BBC app.