As Novak Djokovic’s glorious reign of 122 weeks as the king of tennis edged towards a conclusion with a shock defeat in Paris on Friday, Andy Murray, the heir apparent for 76 weeks stretched over seven years, put one undoubtedly trembling hand on the crown.

Murray, enjoying the season of his life, beat Tomas Berdych 7-6 (11-9), 7-5 in the quarter-finals of the Paris Masters and will replace Djokovic as world No1 if wins his semi-final on Saturday against Milos Raonic. That would erase the 235 points between himself and the Serb and move him past the man who has been his master for most of their parallel careers – but who earlier succumbed to the world No10, Marin Cilic, for the first time in 15 encounters over eight years.

The Croatian’s 6-4, 7-6 (7-2) win in an hour and 44 minutes stunned a struggling Djokovic, who saved two match points despite nursing an injury to his right arm that has troubled him for months, and handed Murray the chance he has worked so hard for, not just the past month or so while collecting titles in Beijing, Shanghai and Vienna but for much of his 11 years on the Tour. Murray said: “Maybe there were a few more nerves before but, once I got out there, no. It was a great atmosphere. It didn’t really bother me. I don’t know [how he will handle the pressure on Saturday]. I’ve never been in this position before. I don’t know how I’ll deal with it. Normally in big matches, when you got on court, you feel fine. If I wasn’t to get to No1 this year, I was looking to next year. If it happens, great. It’s been a great few months for me and I’ll try to finish this week the best I can.”

“But that wasn’t my goal at the start of the week. It wasn’t my goal two or three weeks ago. This is a long-term thing. To get to No1 is not about one match. It’s about a whole season that you put together and 12 months of work. If it doesn’t happen tomorrow, it can still happen in a few months. That is when I [originally] thought I’d have a better chance of doing it. But I’m not putting any extra pressure on myself.”

He also paid tribute to the incumbent. “He’s not just the No1 player just now. He’s one of the best players that’s ever played – just like Roger [Federer] and Rafa [Nadal] have been, as well.”

He said of a dramatic first-set tie-break against Berdych: “I played some good ones, he played some bad ones on the set points, and I just fought as hard as I could. I served pretty well in those moments, better than him. There were a few net cords that went my way. I dealt with the double-fault well. It didn’t affect me.”

His win was littered with the usual sprinkling of magic and angst over nearly two hours on Court Central. In a tie-break that will make any highlights reel of the season Murray came from 6-1 down, saved seven set points, double-faulted with the most horrendous second serve for 8-9, watched a nailed-on Berdych winner drift long after banging the tape and allowed himself a huge, puffed-cheek gasp of relief when a double-fault give him set point at 10-9, on serve. After a shootout that lasted a quarter of an hour Murray put away an angled forehand to leave the Czech rooted to the baseline.

Having constructed a mental mountain for himself after a first set of the highest quality, Berdych, not always the most resilient of players, dropped serve at the start of the second. But, steeling himself to the task, he broke back when Murray, serving for the match at 5-4, thrashed a forehand into the net.

The Czech, who had gone for his shots all night, could not sustain the fightback, however, belting his sixth double fault. At the second attempt Murray had a match-winning serve wrongly overruled at 40-15, battled to deuce and put it to bed with consecutive aces, his fourth and fifth of an excellent match.

Defeat was doubly painful for Berdych as it put him out of contention for the eighth and final place in the ATP World Tour Finals that start in London on Monday week.

Djokovic could not have been more gracious afterwards, acknowledging that Murray, whom he has beaten 24 times in 34 matches, would be a worthy successor as the game’s best player.

“If he gets it, which he is in a very good position to do, he’s definitely a player who deserves that,” Djokovic said, as Murray’s match against Berdych was playing out on TV screens all around him.

“Undoubtedly much respect for what he has done. We have known each other since very early days. We were 11 years old when we first played against each other. And to see how he has raised his level in the last 12 months is quite extraordinary. All I can say is that he’s deservedly in the position he’s in at the moment.”

Djokovic, who had looked so solid as he completed a career grand slam at Roland Garros in the summer, has seen his game slowly fracture around the edges under pressure on and off the court.

He was as honest as he ever has been in addressing his dilemma. There are growing rumours he may soon part company with one of his coaches, Boris Becker, and Djokovic did not provide any evidence to the contrary. “We’ll see. It’s early to talk about it but the team that’s there is there. I’ll see what’s gonna happen for next year.”

As for his own game and ambitions, Djokovic was equally candid. “I didn’t know how I was going to feel [after finally winning the French Open, beating Murray in the final]. At a certain point I had to reach this kind of phase where I had to reflect and say: ‘OK, I have played on the highest possible level for that much time.’ The drop of form is normal in sports. I’m not too concerned about how the future will go for me. I’m just living in the moment and that’s all.”

He added: “It would be disrespectful to all the players that I only talk about myself or Andy, even though we are in two top spots in the world at the moment. There are guys like Marin Cilic, for example, or Stan Wawrinka who are right behind. They keep on pushing, keep on fighting. This is sport. You can’t always expect to win. In terms of what the future brings to me, that’s not in my hands. I’m going to keep playing at this level as long as I feel like that’s the right thing for me.”

But this is Murray’s moment. If he gets to the top of the mountain, he will be the oldest player to do so since John Newcombe, then 30, in 1974, and would join the 25 illustrious players who have ruled since the ATP introduced the ranking system in 1973. And as Djokovic said, no one could say he has not earned it.