The three higher-ranked players in all the matches played so far this tournament have all been defeated.

Zhao Xintong is hoping to end that run tonight, and avoid being the fourth world champion to fall. He is also hoping to join compatriots Wu Yize and Xiao Guodong in the quarter-finals.

Image source, BBC Sport

Hello again. Ready for some more snooker?

We've got the world champion in action tonight.

We're going to pause this page for a bit before the evening session starts at 19:00 GMT when reigning world champion Zhao Xintong of China takes on England's Gary Wilson.

Speaking to the BBC after the match, Mark Allen revealed his preparations had been hampered.

"I felt comfortable, which is weird," said Allen, "I prepare properly for these events but I couldn't prepare for this at all as I'm been lying in bed all week with food poisoning, so I just thought 'go out there and give my best'.

"I wouldn't have had much left it had got much closer."

Allen beat Kyren Wilson to win the 2018 Masters and said he "was not getting carried away" about his hopes for a repeat success.

"This is my 11th quarter-final [at the Masters] but I've only won it once so I have to sort that out - this is as good a week as any to do that," added Allen.

This is how Mark Allen completed his win and then he tells Rob Walker how he has been struggling with food poisoning over the past week.

Mark Allen is through as Mark Williams becomes the third world champion to be eliminated in three matches.

A chance for Allen to wrap this up now.

Mark Allen is 40-2 ahead, with four reds on the table and a safety battle. It is a fight Williams needs to win or he'll be heading home.

A break of 70 to finish off the frame takes Mark Allen one frame away from the finish line.

Mark Williams makes one but misses a long blue and that should be 5-2 to Mark Allen.

Earlier on this frame Mark Allen made 30 then had to play safe after losing position and now he's done this again after adding another 27. That's a 57-0 lead for Allen, but hope for Williams.

No luck for Mark Allen when potting the blue and going into the pack of reds and that brings his break to a halt at 30.

A missed long red from Williams is a bad way for him to start the seventh frame. Allen has a chance to pile on the pressure here.

We haven't seen many frames done in one visit, but a magnificent 125 clearance from Mark Allen is a big step up in quality and worrying signs for Mark Williams.

That's the first century of the match and the 687th century of Allen's career.

It is also the first time either player has held a two-frame lead today.

Mark Williams leaves a red on and that is what Mark Allen needs to nudge back ahead at 3-2.

It's the first to six so we have had five frames, with a maximum of six more to come.

Mark Allen, on a break of 60, leaves the red hanging over the pocket after a miss, but Mark Williams can only get one on the board before missing the black off the spot. The grimace that follows from the Welshman shows he knew that was a good chance.

Allen still has work to do though as he's 43 ahead, with 43 on the table.

Mark Williams can only make 17 from an early chance and that gives Mark Allen the opportunity to move back ahead after he took the first frame of the afternoon.

There was an issue yesterday during the first match when Wu Yize rolled a pink along the top cushion in the third frame of his 6-2 victory over Shaun Murphy.

Six-time world champion Steve Davis was critical of the conditions and said at the time: "I don't want to put a dampener on it, it's January isn't it, that pink along the cushion, the way Wu Yize played it, he knows the table is not level and was going to hug the top rail.

"I don't know if they do, but the table fitters need to check the level of the slate because if the balls are hugging the top rail it's going to make the game incredibly easy to make big breaks. It is not the size of the pockets, which we had at the UK, this looks like it's not level."

A statement from World Snooker Tour said: "The table is checked before, during and after every match, as is standard at any event. We strive to provide the best possible playing conditions and our team of expert table fitters do a fantastic job."

We have just seen a similar situation in the match between Mark Williams and Mark Allen, but this time the red does not roll successfully along the top cushion.

"The table fitters have fixed the problem," said former world champion Ken Doherty on commentary.