As Andy and Jamie Murray prepared for their assault on an unprecedented double here this weekend – No1 in the world in singles and doubles, respectively – the brothers reflected on one of the most remarkable journeys in British sport.

“We’re probably each other’s biggest fans,” Andy said of their relationship after making short work of an underdone Stan Wawrinka on Friday to book a sixth meeting this year against Milos Raonic in the first semi-final of the Barclays ATP World Tour Finals. If he goes on to win his first title here in 10 attempts, he will also hold at bay the late charge by Novak Djokovic for the No1 spot he took from him in Paris 11 days ago. Djokovic plays Kei Nishikori in the other semi-final, and is looking dangerous again.

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“It’s really special to get to watch what he’s achieved in the biggest competitions in the sport,” Murray said of the brother who is 15 months older than him and who has made his name in the less physical but no less artful discipline of doubles, adding two slams to his résumé with his Brazilian playing partner, Bruno Soares, this year. “Neither of us ever would have expected this when we were growing up. We need to try and enjoy it.”

Earlier, Jamie had it confirmed that he and Soares would finish the season as the best doubles team in the world after his former team‑mate John Peers and the Finn Henri Kontinen froze the Frenchman Pierre-Hugues Herbert and Nicolas Mahut out of the rankings equation with a 6-7, 6-4, 10-6 win. “It was a strange way to do it in the end,” Jamie said later. “We’ve had a great year. We didn’t win loads of tournaments but we won the right ones. We had a great start here winning our three group matches and it is really exciting to do it.”

The success of the Murray brothers began, as everyone knows, in Dunblane nearly 30 years ago, inspired by their mother, Judy, and cheered on loudly by the rest of their family, including their father, Willie, who remarries there in two weeks’ time.

“We used to play against each other all of the time pretty much until we were like 12 to 14,” Andy said. “That was when we went our separate paths, really. Jamie went down to Cambridge for, nine months or so, then he went off to Paris, and I went off to Spain when I was 15.

“Between 12 and say 17 and 18, we didn’t spend loads of time together. But before then, pretty much every time we went to practise or play tennis, it was together. We played probably four hours a week. It wasn’t like loads. But we did play golf together. We played squash together, table tennis. We were always competing against each other from a young age. Now we obviously don’t.”

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And who was better, who hurt more, who was more competitive? He paused, adding: “When we were really young, Jamie would have won most things we did. He was 15 months older, so he was bigger and stronger and better than me at most things. He was smarter than me. As we got older and physically were on more of a level playing field, we were pretty close at most things. Jamie is a really good golfer. He was better at that. Football, probably me. Squash and table tennis, more of the racket sports, it was pretty close between the two of us ... Well, that’s my recollection of it. He might say something a bit different.”

Still scrapping brothers, after all these years.

As for the challenge ahead, Murray knows better than anyone inside or outside his world that Djokovic is as lethal now as at any time in his career, wounded but regathering the strength that ebbed from his body and spirit after a shock early exit at Wimbledon, and, if they meet in the final on Sunday for the 35th time, it is likely to be as intense an examination of their wills as the best of the other contests. The Serb was hugely impressive when defeating the late substitute David Goffin on Thursday night.

Murray’s 6-4, 6-2 win in an hour and 26 minutes against Wawrinka was good but, apart from the first half-hour, it was not much of a contest. Murray broke once from four attempts in the first set and took two of three chances in the second, serving out untroubled, adding just his third ace and then forcing a final dreadful forehand from Wawrinka, who looked more relieved than devastated.

Wawrinka’s 29 winners just edged his unforced errors (27), but they were not all the result of adventurous tennis; there were a lot of what cricketers call “get out shots”‚ balls flying wildly from all parts of his uncontrolled racket.

Murray’s game was far more disciplined. He won 67 of the 118 points contested and did pretty much everything needed to put away a dangerous opponent who plainly was off his game.

As the Swiss said later: “He made me hesitate – when to go, when to stay back. That’s why he’s so good. That’s why he’s No1. He’s full of confidence.”