Seven-time champion Ronnie O'Sullivan cruised into the quarter-finals of the Masters with a 6-1 victory over Jack Lisowski at Alexandra Palace.

Lisowski made a break of 108 in the second frame to get back on level terms after O'Sullivan won a scrappy opener but missed a routine green in the next and watched O'Sullivan make an 86 clearance to move 2-1 ahead.

A break of 63 extended O'Sullivan's lead and he returned from the mid-session interval with a total clearance of 127 and further contributions of 64 and 125 to the delight of the partisan crowd.

"I struggled early on, I was really, really nervous," O'Sullivan said in a post-match interview.

"It's such a big crowd, we've been playing behind closed doors for so long I forgot what it was like to play in front of a crowd, let alone a crowd like this full of mad Londoners.

"I was feeling the pressure, but after the second frame I calmed down a bit and thought, okay, let's just try and play snooker and I played all right."

O'Sullivan, who will face Australia's Neil Robertson in the last eight, added: "I'll just savour every match I play - 20 majors, most successful player of all time.

"I've just got to keep thinking of that and take that into the match and let him worry about me."

Tuesday's evening session saw world number one Mark Selby eventually end Stephen Maguire's challenge to progress 6-3.

After Selby took the opening frame which lasted 45 minutes, a break of 87 from Maguire soon levelled things up.

There remained little between the pair until Selby put himself in front 4-2 following a clearance of 64 and then moved to within sight of victory by edging the seventh frame.

World number 11 Maguire, though, rallied again with an unanswered break of 84 to reduce the deficit at 5-3, but Selby eventually closed out a tense ninth frame 59-20 to set up a quarter-final against Barry Hawkins.