Andy Murray
Murray gave his Tour Finals campaign a lifeline with a vital win over Raonic.Getty Images/Julian Finney

Andy Murray kept his ATP World Tour Finals hopes alive with a straight sets win over Milos Raonic at the O2 Arena in London.

The world No.6 won 6-3 7-5 to claim his first round robin victory of the tournament and give his ambitions of reaching a fourth semi-final as the season-ending tour finals a much-needed boost.

Murray faces six-time champion Roger Federer in his final match knowing that victory will all-but guarantee his passage into the last four while Kei Nishikori and Raonic face off in the other group match.

Following Federer's two-set win over Nishikori in the afternoon session, Murray knew only victory would keep his hopes alive in the climax to the ATP season and prevent the ignominy of being the first player knocked out in London.

Raonic had the luxury of knowing even a second loss of the round robin phase would keep him in contention going into his final match, and having won three of the pair's previous meetings was well placed to claim a first ever win on his ATP Finals debut.

The enormity of the contest ensured both players began in nervy fashion but the first chance to gain a foothold came the way of Murray in game three after three loose forehands from the Canadian but he survived two break point chances despite his first serve evading him to level at 2-2.

But Murray didn't have to wait long for his next opportunity, setting up a third break point of the set thanks to a delightful sliced-backhand into the corner before another wayward Raonic forehand helped convert the opportunity.

The 23 year old's accuracy returned to end a three-game streak from the British No.1 but couldn't prevent Murray from converting his third set point to climb into the ascendency.

Threatening to fold early in the second set, Raonic recovered from 0-30 to hold in his opening service game but faced a break point following an untimely double-fault before a backhand into the tramlines again handed Murray the initiative.

It was however an advantage the Briton was unable to seize as the errors flowed from the Murray racquet to allow Raonic to break back immediately.

The extent of Murray's error was being realised as Raonic's first serve percentage continued to grow, with the Olympic singles gold medallist's opportunities becoming all the more rare despite his opponent's misfiring forehand.

However, just as Raonic looked at his most comfortable Murray upped his game; producing a brilliant cross-court backhand on the run on the way to setting up two break points which he converted at the first time of asking.

And it would be a position Murray would not relinquish as he retained hope in reaching the semi-finals by serving out the match in dogged manner.