Mark Selby threatened to squeeze the life out of Shaun Murphy as he seized the advantage in the second session of their World Snooker Championship final at the Crucible.

Selby won seven out of nine frames on Saturday evening to turn a 5-3 deficit into a 10-7 lead heading into the conclusion of the best-of-35-frame encounter on bank holiday Monday.

Selby's success in sapping his opponent’s swashbuckling spirit prompted Ronnie O’Sullivan, appearing as a pundit on Eurosport, to liken the three-time champion to a "boa constrictor" and warn: "He will tighten even more."

Murphy had stomped into the final after reeling off seven straight frames to sink Kyren Wilson and the 2005 champion looked set to make good to on his vow to entertain after winning the first two frames of the match.

But squashing Selby, who was unrepentant after being warned for slow play in his semi-final win over Stuart Bingham and had vowed to fight for "five years" if required to dredge up a victory, would prove easier said than done.

Murphy missed an effective frame ball for a 3-0 lead, and Selby, who had overcome much greater deficits in two of his previous successful world final bids, duly clawed his way back to level the match at 2-2.

Murphy will be aiming for a second title tomorrow

But Murphy managed to regain the upper hand during a tight opening session, and it was Selby who left the arena with more to ponder after a missed red in the eighth frame enabled his opponent to secure his early advantage.

Few, least of all Murphy, would have expected anything less than a Selby fightback when play resumed in the evening, and the Leicester man duly obliged with an 85 clearance to narrow the gap to 5-4.

Murphy responded again with a break of 98 to re-establish his two-frame lead, but there were ominous signs that Selby was gaining the ascendency, and he took the next two frames to pull level at 6-6.

Again Murphy nudged back in front, but it was to prove his last significant contribution of the night, as Selby took two visits to level at 7-7, then summoned a 90 clearance after Murphy left him a tempting long red in the next.

Selby took the 16th frame to move two frames in front for the first time in the match, making it imperative that a visibly tiring Murphy, who had been shut out for almost an hour, take the final frame of the session.

An uncharacteristic error by Selby gifted Murphy the first chance, but he failed to take it, missing a black off its spot then fluffing an attempted safety to give Selby an opportunity to extend his lead.

Selby faltered again, missing a relatively simple blue to curtail a potentially frame-winning break of 40, but Murphy failed to capitalise, Selby inevitably getting the better of an extended period of safety play to slide into a three-frame overnight advantage.