Neil Robertson leads John Higgins 5-3 after a protracted first session of their World Championship quarter-final.
It was an afternoon of struggle for both men as playing conditions remained difficult, and perhaps Higgins could be excused for a slow start given his comeback to down Ronnie O'Sullivan the previous day.
After a counter-punch 61 to take the first frame was cancelled out by Robertson's similar 77, it was then the Aussie who took the lead only to be pegged back as both players struggled for fluency.
With the threat of being hauled off to make way for the evening session looming, it was Robertson who broke the deadlock to take the final two frames and the first of them felt like the first real blow struck in this fascinating quarter-final.
Higgins had looked set to ensure he couldn't lose the session only to miss the 15th red, which Robertson later potted on his way to a run of 70, the type of clearance for which Higgins himself has always been known.
Fittingly, the session ended with a frame which lasted almost an hour and it again went to Robertson, who has won the first battle but knows there are more of those to come.
Also on Tuesday, Hossein Vafaei won the final two frames to level things up with Wu Yize, the pair locked at 4-4.
And to further promise a thrilling climax to the final round before the one-table set-up, both other quarter-finals ended the day locked together at 8-8.
World champion Zhao Xintong took the final two frames to level with Shaun Murphy, perhaps an ominous sign for the latter who had chances to press home his advantage against an opponent who looked all at sea early on.
Barry Hawkins and Mark Allen meanwhile exchanged blows in a world-class finish to their second session, Allen's breaks of 138 and 131 sandwiching a 140 from Hawkins, who then took a scrappier 16th frame to level the match again.
They'll play to a finish on Wednesday afternoon, with the other two quarter-finals set to end this evening.
