Mark Allen will wake up this morning knowing he had a far better World Championship than he had any right to expect.

But Allen — who has been facing off-the-table problems — will also have the nagging feeling he could, and probably should, have given Mark Williams a tougher match in the quarter-finals of the £1.1million tournament.

Williams wrapped up a comfortable 13-5 victory yesterday but it was Tuesday’s opening session — which the Welshman somehow managed to win 5-3 despite being under the cosh — that both players cited as a turning point.

“I played probably the best snooker I've played in the tournament and managed to somehow throw three frames away,” admitted the Antrim cueman.

“I made 59, 60 and 66 and lost all three frames,” added Allen.

“I should have been 6-2 in front but somehow I came out 5-3 down.

“But that's what Mark does best. He knows how to win and he knows how to get the most out of a session which is something I'm still learning to do.

“From then on it was a bit of a struggle to hang on to his coattail and he showed what a class player he was by pulling away so easily,” said the 25-year-old.

Allen had been receiving treatment for depression before the World Championship and, in his own words, ‘can probably count on one hand the number of times I've lifted my cue’ since the German Masters in February.

He came into the tournament facing the prospect of needing to win a difficult opener against two-time finalist Matthew Stevens to retain his place in the game’s elite top 16.

At 9-6 down in the first to 10 encounter things didn’t look good for Allen but he showed true grit to pinch an emotional 10-9 win, cheered on by his four-year-old daughter Lauren from the front row.

And he also needed a deciding frame to get past Barry Hawkins in round two, winning 13-12.

“I'm happy with the way I fought but I didn't deserve to play at my best with the amount of work I had put in,” said Allen.

“I wasn't prepared at all for this tournament and you're going to be found out against the top players.

“Winning a couple of close matches has given me a bit of hunger back for the game which I had lost. It has given me some self-belief that I can do it and that's something I had lost.

“There was never a question of me pulling out but against Matthew in the first round I didn't want to stay out there. But there's something ingrained in my mind that doesn't let me give up.

“I've turned a lot of neutrals on my side as they've witnessed my style of play and if I keep doing that then I'm going in the right direction.”

Allen’s progress came to a halt against Williams, who has reached the last four for the first time since 2003, the year he landed his second world title.

And Williams admitted the opening session against Allen turned the match on its head.

“How I managed to be 5-3 up I'll never know,” he said.

“He was knocking in 50s and 60s for fun really, and I kept clearing up and nicking them.

“It probably hurt him a little bit early on.”

Meanwhile, 21-year-old Judd Trump yesterday completed a 13-5 win over Graeme Dott.