Andy Murray into the final of the ATP World Tour

Andy Murray gestures on court during his men's singles semi final against Milos Raonic at the ATP World Tour Finals at O2 Arena. (Photo: Julian Finney/Getty

Where he will find the energy is anyone’s guess but after his heroics this week at London’s O2 Arena, no-one would put it past him. Yesterday he shattered his own record for the tournament’s longest match (set on Wednesday against Kei Nishikori) to beat Milos Raonic 5-7, 7-6, 7-6 in three sweat-drenched hours and 38 nail-biting minutes.

After three hours and 22 minutes, the two men were locked at a set apiece and six games all. They had both given almost all they had and there was not a gnat’s whisker between them: 127 points each on the scoreboard. And then as the London crowd roared their approval, they set off on the rollercoaster ride to end them all.

Just to get to this point, Murray had twice served for the match and been thwarted as Raonic used every ounce of his strength and nerve to break him. Once into the tiebreak, Murray had three match points snatched away from him. Then he had to save a match point. And then, at last, something had to give. It was Raonic with a final forehand into the net. Victory was Murray’s.

“I think it was pretty dramatic,” Murray said. “Both of us had chances. In the tiebreak, I think we played some pretty good stuff in the tiebreak. I don’t think it was, like, bad points that we were losing or bad shots we were losing. As points, I think we played some good stuff in the breaker.

“But it was one of the tougher matches I played this year with it being very long, but also mentally tiring as well. The nature of it was very up and down.”

It took him an hour and half to reach the conclusion that if he went for his shots, if he committed to hitting the ball, it tended to stay hit. Until that point, Murray had been the living embodiment of the Clash’s hit, ‘Should I Stay or Should I Go?’ He could not for the life of him work out whether he wanted to wear Raonic down, staying firm and patient on the baseline, or to bloody his nose by going for an all-out attack. And for much of the first set, he did neither.

Raonic, who had endured two successive final defeats at the hands of the Scot at Queen’s Club and Wimbledon earlier in the year, was doing everything that was expected of him. He was serving with relentless precision and power, he was attacking the net whenever he could and he was returning Murray’s serve with alarming accuracy. There were no weak spots for Murray to aim at, no hesitancy to pounce on: Raonic was as solid as a rock and Murray could not find a way to bruise him, much less hurt him.

By the time Murray was facing two break points at the end of the first set, Raonic had dropped just five points on serve while Murray had dropped 15. When he then offered up his serve with a double fault, the alarm bells were already ringing.

But Murray’s climb to the top of the rankings this year has been built on grit and determination as much as god-given talent. He has won when he has not been playing well; he has won when he is tired and he has won when he thought he had nothing left to give. And yesterday, he was determined to win no matter what.

“I fought really hard today,” Murray said. “I fought very hard this week. I have also the last few months, too. It would have been easy today when I was behind to have gone away a little bit, but I didn’t. Even after serving for the match twice, having a bunch of match points in the tiebreak, still stayed tough, chased balls down, fought as best as I could. It was enough to get me the win. Yeah, I was happy with that.”

At a set and break down, Murray attacked. He broke back. It was a lifeline, however thin and fragile. But he clung to it and chased and harried for all he was worth. He would not let Raonic settle; the Canadian was not going to imagine that he could boss the match. And slowly but surely, he reeled Raonic in until his prize catch was landed. Only this morning, ahead of his showdown with Novak Djokovic, who swept past Kei Nishikori 6-1, 6-1 last night, will he discover at what cost the Raonic victory has come.