John Higgins won seven of the evening session's eight frames to move into a potentially decisive 11-5 lead over Shaun Murphy.
Scot takes control at the Crucible
John Higgins won seven of the evening session's eight frames to move into a potentially decisive 11-5 lead over Shaun Murphy in the World Championship final.
The two-time former champion was particularly impressive after the mid-session interval and barely let Murphy get a glimmer of a chance as he swept up the last four frames.
The highlight was a 128 total clearance to go 9-5 ahead and he added breaks of 58 and an imperious 122 to win the final two frames of the evening.
The 33-year-old Scot needs to win a further seven frames on Monday to claim a third world crown, while Murphy - world champion in 2005 - has left himself with a mountain to climb.
No player has come back from an 11-5 deficit in the final to be world champion in Sheffield.
Opening session
Earlier, in the match's opening session, the pair shared the spoils as it ended 4-4.
Higgins struck first when he opened up a 3-0 advantage, but Murphy then hit back with four frames on the bounce to go ahead.
However, 'Wizard of Wishaw' Higgins hit back to take the final frame.
Higgins made a bright start to the match, with a break of 78 giving him the opening frame, while runs of 33, 52 and 43 saw him move 3-0 ahead as he settled quicker.
UK champion Murphy has shown his form over the longer matches already this season, and his calm break of 58 got him on the board.
He then gave away 28 points from a testing snooker in the fifth frame, but still managed to take it to reduce the deficit to just 3-2.
The first century of the final then came from Murphy's cue, with a superb 109 taking the tournament tally up to 81, 13 more centuries than the previous tournament record.
A fourth frame in a row came for Murphy after Higgins knocked the blue over the pocket from a snooker, allowing Murphy to clean up.
Higgins is the ultimate match-player though and ensured that he would not trail going into the second session with a steady break of 50 helping him to the eighth and final frame.
