A break of 91 in the first frame gave the 1998 world champion an early advantage, before this season’s Masters champion O’Sullivan won the next with a break of 89.

However, Higgins then won the next two frames, the highlight of which was a run of 73 in the fourth frame.

The two tournament favourites resumed in fine fettle after their mid-session cup of tea, particularly O’Sullivan, who hit back in quick time to level matters.

Breaks of 54 and 65 were enough for the fifth frame, before a run of 60 in the next left the match finely poised at 3-3.

Higgins moved up a gear and sunk a match-high break of 110, but Chigwell potter O’Sullivan made sure honours were shared as he took the last frame of the session with a 76 break.

The pair resume to conclude their match tomorrow, with the winner set to play either Nottingham’s Anthony Hamilton or Glasgow’s Stephen Maguire.

They will play a morning session of a maximum of eight frames, with the conclusion of the match due to take place in the evening session.

Maguire took a 5-3 lead over Hamilton in their first session of their best-of-25 frame encounter.

The former UK and European Open champion won a scrappy opener before a break of 63 saw the four-time ranking event quarter-finalist draw level.

Maguire won the next with a cool 106 break, before Hamilton pocketed runs of 79 and 42 to go ahead for the first time in the match.

But from then it was Maguire’s turn to control proceedings, a break of 42 and a clearance of 25 enough to take the sixth frame, before a superb break of 89 made it 4-3.

It soon became 5-3 when Maguire won the final frame on points 61-15 for a two-frame lead.

Former winner Shaun Murphy and Matthew Stevens are locked at 4-4 after the first session of their eagerly-awaited match.

Playing each other for the first time since the 2005 Crucible final which Murphy won 18-16, it was Welshman Stevens who started the better.

Breaks of 46, 118 and 64 saw the two-time finalist race into a welcome 3-0 lead.

However, back came Murphy with a break of 82 to make it 3-1, before winning a scrappy fifth frame to trail 3-2.

Stevens sunk another century, a break of 108 to win the next frame and give himself a two-frame cushion.

However, this year’s Malta Cup champion Murphy was in determined mood and breaks of 33 and 89 saw him win the next frame.

Stevens started well in the final frame of the opening session, but missed his chances and Murphy won the frame with a composed 33 break.