Andy Murray kept his narrow Masters Cup hopes alive by booking his place in the St Petersburg Open final with a thrilling victory over Mikhail Youzhny.

The British number one wrapped up a 6-2 5-7 7-6 win in a little over two and a half hours against the Russian - one of his rivals for the remaining places at the elite end-of-season tournament.

With just three ranking places separating the pair - who had never met before - a close encounter seemed on the cards, but two Murray breaks in the opening three games put him firmly in charge.

Youzhny finally held serve to make it 4-1 but rarely threatened his opponent as Murray served out to take the opening set.

The world number 19 finally forced a break point on the Murray serve in the fourth game of the second set, but Murray dug deep to hold.

The 25-year-old Russian was much improved in the second set and it went with serve until a late break of Murray's otherwise strong service saw Youzhny take the set 7-5.

Murray, 20, was suffering through unforced errors and forehands into the net and then beyond the baseline saw him broken in the fourth game of the decider.

Immediately he had two points to break back, but Youzhny found powerful serves to eventually hold for 4-1.

After three more games the home favourite served for the match but Murray dug in and claimed a match-saving break to stay alive.

Youzhny forced a match-point in the next game only for the Briton to scramble for a morale-boosting hold to make it 5-5.

The match went to a tie-break and Murray raced into a 4-0 lead before Youzhny's double fault handed him a 7-1 win and a place in the final where he will meet either Marian Cilic or Fernando Verdasco.