Judd Trump survived a final-frame decider as world number six Mark Allen joined Ronnie O’Sullivan in making a shock first-round exit at the World Championship.

Trump recovered from 6-3 down overnight and held his nerve to produce a break of 53 in the last frame to edge past Thailand’s Thepchaiya Un-Nooh 10-9 at the Crucible in Sheffield.

But Allen was unable to complete an even better comeback against China’s Zhou Yuelong, the Northern Irishman winning five frames in a row from 9-2 down before Zhou won a nerve-racking 17th frame to seal a 10-7 victory.

Trump will face China’s Ding Junhui in the last 16 in the bottom half of the draw, which has opened up following five-time champion O’Sullivan’s defeat to amateur James Cahill on Tuesday.

However, the 29-year-old Masters champion admits he will need to raise his game against 2016 finalist Ding and was probably one of the only players not happy to see O’Sullivan make an early exit.

“I probably play a little bit better when I play the top players, so hopefully now I can raise my game to how it has been in the Masters or a couple of the other tournaments I’ve won,” Trump said.

“All my big titles seem to come when I play Ronnie. I didn’t look at it as a good thing him going out, I always cherish playing him and especially at the Crucible it would have been amazing.

Judd Trump during his 10-9 victory over Thepchaiya Un-Nooh during day five of the 2019 Betfred World Championship at The Crucible, Sheffield
Judd Trump during his 10-9 victory over Thepchaiya Un-Nooh during day five of the 2019 Betfred World Championship at The Crucible, Sheffield (Nigel French/PA)

“I need to go back and practice properly, stick four or five hours’ practice in for the next couple of days and come back as a new man hopefully. The way Neil (Robertson) is playing he’s definitely the favourite.

“I’m one of the people that have got a lot to prove here. A lot of the other top players have already won it, so they’ve got that experience, and I’m hopefully going to be able to settle down and really enjoy the game against Ding now.”

Breaks of 82, 62 and 68 helped Trump win six of the first eight frames of the day to lead 9-8, but qualifier Un-Nooh produced a break of 78, his highest of the match, to force a decider.

A risky cross-double set Trump on his way to a break of 53 and, after the break came to an end, Un-Nooh suffered an unfortunate miscue in attempting to escape a snooker and a relieved Trump was able to get across the line.

Allen trailed 7-2 overnight and lost the first two frames when the match resumed, before breaks of 68, 60, 72 and a total clearance of 131 kept his hopes of equalling the biggest comeback in Crucible history alive.

The left-hander won a scrappy frame to make it 9-7 but Zhou came out on top following a safety battle on the final red and cleared to the pink to set up a last-16 tie against either Jack Lisowski or Ali Carter.

“You can’t be playing the way I played in the first 11 frames and deserve to
win a match, it was embarrassing,” Allen said. “But looking back I don’t think I would have done anything different.

“I prepared as well as I ever have. I didn’t go to the China Open, partly because my mother-in-law wasn’t very well – she was in intensive care but is over the worst now, touch wood – but also because my game wasn’t in good shape, so I went to see Terry (Griffiths, his coach) for a few days and try to get myself ready for here.

“I lost a bit of weight, prepared really well, so it wasn’t meant to be. I found a bit of form from 9-2 and really fancied the job from 9-6. It felt like I had him on the ropes and I’m proud of the way I hung on but it’s a disappointing end to the season.”

There was no such drama for Barry Hawkins, who made short work of China’s Li Hang with a commanding 10-1 victory.

Kyren Wilson will resume 6-2 up on Scottish rookie Scott Donaldson, with Hawkins awaiting the winner in round two.

Two-time Crucible runner-up Ali Carter leads Jack Lisowski 5-4.