Welshman Mark Williams ended the second session with two centuries to lead Northern Ireland's Mark Allen 11-5 in their World Championship quarter-final.
Resuming at 5-3, the two-time champion knocked in two breaks of 80 but Allen stayed cool to get it back to 8-5.
Williams, world number three, stepped up the pace and knocked in a 104 and 113 to take firm control.
Judd Trump looked set for an early win, before Graeme Dott, who missed out on a maximum 147, fought back to trail 11-5.
It was an incredible, battling performance from Dott, last year's runner-up and the champion in 2006.
The 21-year-old Trump started the evening with a 7-1 advantage after dominating the morning with breaks of 86, 64, 58 and 55.
And it got even better for the recent China Open winner, who raced into a 11-2 lead, thanks to a 104 and 79.
The match looked certain to end a session early when a frustrated Dott fouled the red when venting his anger at a poor positional shot, but the gritty Scot then hit back with three successive frames to give himself a glimmer of hope.
He had even looked set for a maximum 147 in the 15th frame after potting 15 reds and 15 blacks, but watched in agony as the cue ball ran astray with just the colours remaining.
Dott's run of 122 in the evening's final frame ensured Bristolian Trump has plenty to think about ahead of their final session on Wednesday morning.
On the other table, Williams, eyeing a third world crown after glory in 2000 and 2003, showed exactly why he should be rated as one of the favourites to win this year's tournament.
The Welshman, back to a provisional ranking of world number one, had built up a 5-3 lead in the morning session with a 95% potting success rate and a top break of 125.
Antrim's Allen showed plenty of character with breaks of 100 and 102 but struggled throughout the evening, securing just two frames out of the eight on offer.
Williams, 35, opened up with an 80 to edge 6-3 ahead and after a scrappy two frames, it was soon 8-4 with another run of 80.
Allen remained within touching distance to nab the frame immediately after the mini-break and reduce the deficit to three, only for Williams to produce a masterclass in potting and staying calm.
Knocks of 104 and 113 in the session's last two frames - his 32nd and 33rd ton at the Crucible - left a deflated Allen stuck in his chair as his opponent secured a commanding position, needing just two for victory.
Both quarter-finals resume at 1000 BST on Wednesday.