John Higgins secured a narrow 13-11 lead over Shaun Murphy after a gripping session at the Crucible Theatre, setting up a dramatic final day in their World Championship semi-final.
The four-time champion, who turns 51 this month, had not led at any session break during the tournament but chose the perfect moment to change that. He now stands one session away from a record-equalling ninth world final.
Murphy, the 2005 champion, struck first in the evening session with a break of 60 to take the lead for the first time since the seventh frame. But Higgins responded immediately with runs of 44 and 55, then edged ahead by snookering Murphy on the brown.
Murphy leveled with a superb 82 before the mid-session interval. The pair then traded frames in spectacular fashion, with Higgins crafting a 63 and Murphy countering with a century from Higgins' break-off.
At 12-12, a drawn session seemed likely. But Higgins dug deep, producing a run of 70 and a magnificent 101 to grab the lead going into Saturday's final session.
"It's what John Higgins has done in every match this championship - he's got better as each match has gone on and played his best snooker near the end of the match," said seven-time world champion Stephen Hendry.
"That's the best John Higgins has looked in this semi-final. Since the interval that's breaks of 63, 70 and a century - clinical, one-frame snooker," added former semi-finalist Joe Perry.
The deciding session begins at 14:30 BST on Saturday, with the winner facing either China's Wu Yize or Northern Ireland's Mark Allen in the final.