Ronnie O’Sullivan hailed the impact intermittent fasting has had on his energy levels during this year’s World Snooker Championship after seeing off Ryan Day to reach the quarter-finals.

The 48-year-old, who is bidding to secure a record eighth Crucible crown, eased his way into the last eight after winning three of the four frames on Monday afternoon to wrap up a 13-7 victory against Welshman Day.

O’Sullivan revealed the challenge of negotiating a 17-day marathon in Sheffield is being made easier by intermittent fasting, with the Englishman going around 16 hours without food before breaking his fast in a bid to boost his energy.

He said: “I just do what’s right for me. It’s not like I sit down with someone and work out what’s right, what’s wrong and how to peak. A lot of people think I do.

“What I do is I try to eat right. I’m intermittent fasting for this tournament because it gives me more energy.

“There’s certain things I do and it doesn’t necessarily mean I’m going to win, I just need every little advantage I can get at this stage.

“This is a tournament of endurance, stamina and concentration. For me, intermittent fasting just gives me a bit more energy.

“Once the tournament’s over, I’ll be back to eating 24 hours a day. There’s times when you have to work out what’s right for you.

“I go a certain period of time where I won’t eat and it’s just amazing the energy you get from it. I’ve always found it works really well for me.”

O’Sullivan revealed that he first discovered the benefits of intermittent fasting after a period of illness.

He added: “I got ill and the only way to give my stomach a rest was by not eating. My nutritionist said ‘the only thing you can do is not eat’ but obviously you have to eat.

“I was doing it and I went ‘you know what, I love this, it’s great’. I just felt it worked for me.

“That’s 16 (hours) at the moment, 17 sometimes. I try to stop at about 7pm but it’s hard obviously when you’re playing matches. Last night was 8.30pm so I didn’t eat again until about 12:20pm today.

“It feels great, I feel good. I’m 48 and I feel energised. If I eat too much I get really sluggish.

“Animals in the forest apparently go days without food and then all of a sudden they get hungry, get their prey, eat it and just digest it for a while. They’re not having three meals a day, it’s just eat when you’re hungry and give your body a rest sometimes.

“It works for me anyway.”

John Higgins summoned one of the great Crucible breaks to sink Mark Allen 13-12 and reach the quarter-finals for the 18th time in his career.

Coming to the table 62 points down in the decider, the 48-year-old played a nerveless double on a red to the middle, and later nailed a red down the top cushion that Stephen Hendry, commentating on the BBC, called “one of the best shots I’ve ever seen”, as he fashioned a 71 clearance to snatch the match.

Higgins had resumed trailing 9-7 and fell a further frame behind before he chiselled a gutsy comeback that ultimately secured his place in the top 16 for next season – and left Allen still waiting for his maiden world crown.

Higgins will next face Kyren Wilson, who won the three frames required in the afternoon session to complete a 13-6 win over Joe O’Connor.

Former champion Stuart Bingham sealed a last eight clash with O’Sullivan after winning the last two frames to overcome Jack Lisowski 13-11.

Lisowski had hauled level with consecutive breaks of 88 and 123 but Bingham, who had battled through qualifying after falling out of the top 16, held his nerve to keep his dream of a second title alive.