Ronnie O’Sullivan has put himself in prime position for an 18th Betfred World Championship quarter-final after opening up a four-frame lead over Shaun Murphy.

The five-time world champion locked horns with the world Number 5 for the first of three sessions in their best-of-25 encounter, with O’Sullivan leading the way with a 6-2 advantage at the Crucible.

That was largely down to some exquisite snooker, making five 50-plus breaks in the opening eight frames of what was already an eagerly-anticipated round two tussle.

But Murphy showed he was not down and out just yet, delivering a shot of the tournament candidate to give himself a hope of replicating his 2005 title success.

Both players started in quite brilliant fashion as each of the first five frames had a sizeable score, with the Chigwell-based world Number 12 the first to draw blood with a break of 91.

Murphy is in good form himself however, and responded with a break of 84 in double-quick time, with a mistake from either player being capitalised on with ruthless potting.

But from there O’Sullivan kept the former world champion in his chair right through until the mid-session interval, following up a break of 75 with an effort of 128 – which would have been 135 had he not potted the cue ball – the latter coming in approximately six minutes.

That left O’Sullivan with plenty to smile about come the halfway point of the evening, and he again raced out of the blocks after the interval with a 76, while the next frame saw him open up a four-frame advantage at 5-1.

That was not without some audacious snooker from Murphy, though, seemingly snookered behind the yellow only to use two cushions and plenty of side spin to pot a red into the left centre – an effort O’Sullivan himself would likely have been impressed by.

A shot worthy of his Magician nickname, Murphy then took the key seventh frame in which both spurned numerous chances, eventually decided on the black as the gap was reduced back to three.

But O’Sullivan turned the screw once more to ensure the overnight advantage was four as opposed to two – something which could prove vital in a match where neither player look likely to give an inch.

That was courtesy of a break of 74, leaving Murphy without a pot in the final frame of an enthralling session.

Watch the Snooker World Championship Live on Eurosport and Eurosport Player, with Colin Murray and analysis from Jimmy White and Neal Foulds