The scoring flurry featured an extravagant 143 from Selby that briefly put him at the head of the queue for the tournament's £10,000 top-break prize, before being leapfrogged by Ronnie O'Sullivan's 146 in defeat against Ding Junhui.

Selby frequently ran out of ideal position but produced a host of cavalier pots, including terrific blacks to the left middle and green pockets and a run of exhibition shots.

It was an extraordinary effort, and defending world champion Selby said: "I think it was a good break because I was never in position.

"I just kept potting silly balls from nowhere. I got to about 80 and thought it was the end of the break, and I potted a black into the middle, potted a red down the rail, but when I got down to the black I was more nervous than in any part of the match.

"I was really, really happy to knock that final black in as well. It was a freaky break."

It followed runs of 132 and 139, as Selby demonstrated why he has been world number one for the last two years.

Fu was full of admiration for the 33-year-old, who is chasing the £375,000 top prize and plays Ding next, starting on Thursday afternoon.

"He's unplayable at times. You've got to make him the favourite now after that performance," Fu said.

Four-time former champion Higgins comes into the picture too, from the opposite side of the draw.

He was similarly convincing in sweeping past Kyren Wilson 13-6.

Higgins beat Judd Trump to take the 2011 world title, since when his best run had been a quarter-final showing last year.

But it is a more confident Higgins this year, and the 41-year-old is convinced he can land another championship.

"I believe I can, yeah, and it's a great feeling to have," said Higgins.

Higgins sympathised with Wilson, whose cue tip split in the first session of the match.

"He was desperately unlucky," Higgins said. "That's a big moment during the game and obviously for me it's worked out well."

Wilson attached a new tip but said it "felt like a Fruit Pastille".