Andy Murray
Murray needed four match points to complete another thrilling victory at the ATP Finals.Getty Images

Andy Murray recovered from match-point down to reach his maiden final at the ATP World Tour Finals after overcoming Milos Raonic in a pulsating encounter in London. Murray is one win from securing the year-end world number after coming back from a set and a break down to prevail 5-7 7-6 7-6 to defeat a spirited Raonic, in a match where the scoreline only tells half the story of an unforgettable contest.

A career-record 23rd win in a row looked unlikely when Raonic took the opening set and broke for a 2-0 lead at the start of the second. But Murray showed the fighting spirit which had taken him to the summit of the men's game and stormed back to take the second set 7-5 in the tiebreaker.

Murray and Raonic continued to exchange blow and counter-blow during a thrilling third set. Four breaks in a row saw Murray twice fail to serve out the match after breaking Raonic, before three match points came and went during a thrilling tie-break. Raonic himself missed the chance to reach his first final at the ATP Finals, before Murray eventually secured victory in a match last three hour and 38 minutes.

Defending champion Novak Djokovic or Kei Nishikori will face-off in the second semi-final at 8pm GMT. Defeat for the Serbian will confirm Murray as the year-end number one, while Nishikori can remain in contention to finish as world number three should he triumph.

A repeat of the Wimbledon final saw both players look to break new ground and reach their first final at the season-ending tour championships. Murray had won his last seven matches against Raonic - while his withdrawal from their last scheduled meeting at the Paris Masters had sent the Briton to world number one.

The world number three-chasing Raonic now had Murray's continued presence at the top of the ATP standings in his hands in his first semi-final appearance. Despite a dismal run against the Olympic singles champion he had excelled amid the fast conditions on the match court at The O2 Arena.

Neither player gave an inch in the opening four games, until Raonic produced an uncharacteristically sublime backhand return which brought up the first break point. But the much improved Murray's second serve kicked up at the world number four and freed the 29-year-old from danger.

Milos Raonic
Raonic pushing Murray all the way before eventually succumbing to the world number one.Getty Images

The first sign of nerves from Murray came as he served at 4-4, with a time violation from umpire Fergus Murphy handing Raonic three separate break points. But on each occasion Murray showed the mental fortitude required to wriggle free despite Raonic throwing everything at the number one seed.

As Murray continued to struggle on the Raonic serve - winning just five points in the opening five games - the pressure continue to rein down on his own. Murray eventually wilted as Raonic broke at the fifth time of asking via a double-fault, and held for a sixth time to take the opening set.

But the dynamic of being the frontrunner did not initially sit well with Raonic, who was fortunate to survive two break points when Murray strung together errors on the forehand and backhand side, the latter of which was proving a continual area of weakness. Typically, Raonic used that as inspiration to grab a break in game three, as Murray netted a regulation forehand on the back-foot.

Now in sight of the final Raonic crucially allowed his level to drop and Murray broke to love before completing his most convincing hold of the match to lead 3-2. All the initiative was with the three-time grand slam champion and he had two chances to break for the second time in a row, but failed with consecutive backhands on the run.

Kevin Spacey
Actor Kevin Spacey was among the spectators at The O2 Arena.Getty Images

Murray had won two tie-breaks on his way to beating Raonic at SW19 in July and would require similar success if he were to stay in the match. Raonic dumped a backhand in the net to hand the home favourite the mini break. That advantage was wiped out by two crosscourt forehand winners from Raonic to take him within two points of victory.

A fabulous volley at the net set up the first set point for Murray, which he converted to square the match and drag himself back into contention. The British number one almost undid all his good work in his opening service game of the decider however, but saved two break points to keep Raonic frustrated.

Raonic threatened a critical break when he took Murray to deuce with a superb backhand passing winner, as the match ticked into a fourth hour, but consecutive aces dug him out of trouble. That stubbornness appeared to have proved dividends when Murray benefited from four consecutive Raonic mistakes to break at 5-4.

Andy Murray
Murray looked to have allowed victory to evade him after three match points came and went.Getty Images

Serving for the match proved to be beyond Murray however as Raonic's overhead volley drew him level, with the three-time semi-finalist going to within two points of victory. A third double-fault of the set from Raonic allowed Murray a glimmer of hope again, which handed him a second chance to secure victory.

Another twist in the most dramatic of matches remained as Raonic clinched the fourth break in a row to send the third set into a tie-break as Murray drew blood by striking his fist into his racquet head. Grabbing the mini break, Murray held on and reached match point for the first time as Raonic netted a backhand.

Raonic stayed alive helped by a crushing forehand, but a missed half volley at the net gave Murray a second chance to close it out, but he sent a backhand spiralling long. An ace delivered a third match point which Murray thumped into the net as Raonic resorted to serve-and-volley tactics. The 25-year-old then missed an opportunity himself to claim the win, as Murray kept him at bay.

A fourth match point came for Murray an this time he made no mistake as Raonic netted to spark scenes of jubilation as much in relief as in celebration in Greenwich, to propel him within one win of clinching the year-end world number one.