Ronnie O’Sullivan showed signs of his best form as he took a 5-3 lead on Ryan Day at the World Championship.

Both players made a number of big breaks in a high-quality first session of their last-16 clash at the Crucible.

The ‘Rocket’ got off to a flying start, hitting a 123 break in the opening frame and following up with an 84 in the second to storm ahead.

Day quickly got a foot back in the match, replying with 74 and 78 to draw level after the first four frames, but O’Sullivan recomposed himself after the mid-session interval to restore his two-frame lead with breaks of 83 and 51.

The seventh frame saw Day reduce the deficit following a superb 115 on a difficult table before O’Sullivan quickly cleared 92 in the eighth. The pair will resume in the evening session on Sunday night.

Stephen Maguire secured his spot in the quarter-finals by beating Shaun Murphy 13-9.

The rivals have feuded for two decades following an incident where Maguire was penalised a frame for forgetting his chalk and the Scotsman held off a late fightback from Murphy to seal victory.

He resumed on Sunday morning with a 10-6 overnight lead and continued his quest to reach the last eight with a break of 68 before Murphy pulled a frame back.

Maguire then moved within one frame of victory but Murphy continued to battle, a 67 break earning him the following frame before he took the first after the mid-session interval to trail by three.

However, Maguire sealed victory in style, hitting the only century of the match with a 127 to set up a quarter-final meeting with David Gilbert.

Maguire told the World Snooker Tour website: “(Murphy) looked like he was comfortable in that session, so I was starting to get geared up for a comeback and a close finish. Once I got my chance, I finished pretty well there.

“Me and Dave (Gilbert) get on and we’ve grown up with each other for the best part of 30 years. He is a great player. He’s not had a great season by his standards. I’m probably the same, so we are coming into a good game at the right time.

“The quarter-finals are the pressure matches. I’ve won a couple and lost a couple. It is a match you don’t want to lose in because that arena changes and it does become the best in the world with the one table.”

During Saturday’s session Murphy fist pumped after winning a frame and Maguire admitted it provided him some motivation.

“Shaun made a mistake. He knows me well enough and I get down on myself,” Maguire said.

“He won a frame I should’ve won and I was sitting there hating myself when the fist pump came out and I thought, ‘you’re having it’ and all my attention went on that.

“It was satisfying beating a player as good as Shaun is in the last 16 of the World Championship.”

Mark Allen edged 9-7 ahead in his last-16 meeting with John Higgins in a tight encounter between the pair.

After an even start, back-to-back wins in the 11th and 12th frames put Higgins in front, but Allen then took control by winning the next four frames on the bounce – which included a 94 break – to lead by two.

Stuart Bingham fended off Jack Lisowski’s comeback to also take a 9-7 lead into Monday’s session.

Bingham extended his lead to 6-3 after taking the ninth frame, but Lisowski responded by taking the next three to claw his way back into contention.

However, Bingham finished strongly to take a two-frame advantage into the final session.