O'Sullivan was not at his usual best in Manchester, missing several regulation pots, but by contrast Williams was the man for the occasion.

In a see-saw start to the match, Williams won three of the first four frames to race to a 3-1 lead, before O'Sullivan rallied to win the following four and go 5-3 ahead.

However, Williams then clicked into gear, going on to win seven on the bounce with clinical precision to claim a maiden Tour Championship title.

"I played well all day," Williams told ITV. "I was 3-1 up, and then I went 5-3 down. He played unbelievable I thought, sometimes you've just got to hold your hands up. Tonight I took it to him, I played well.

"Thanks to everybody. I can't believe I won to be honest."

"It's not bad for a part-timer - I'm a part-time pool player now," he added with a laugh.

"I never thought I was going to win tournaments at 48. I'm 49 now and I just won another one, so who knows, the World Championship's around the corner.

"I beat Judd Trump, Mark Allen, Ronnie O'Sullivan; the three best players in the world. I haven't done it the easy way."

For O'Sullivan it was a first defeat in a major final for more than two years, and he paid credit to the man who stopped him winning a sixth title of the season.

"I think he's been the best player, the most consistent player for the last five years," O'Sullivan told ITV. "The way he's been hitting the ball - very rarely does he play a poor match.

"He's just an amazing player, so talented. I think he's better now than he's ever been, he's so compact.

"I tried, I gave it everything this afternoon to stay in the match, but he's just so consistent and so strong. You might get the better in one session but if you don't keep playing top-level snooker he'll just eat you alive.

"He's a deserved winner, a fantastic player - probably the most talented snooker player I've ever seen - and he deserves his victory."