Mark Petchey "was not shocked" to see Britain's Kyle Edmund beat Grigor Dimitrov to set up an Australian Open semi-final clash with Marin Cilic.
The 23-year-old continued his remarkable exploits by defeating Dimitrov 6-4 3-6 6-3 6-4 to become only the second British man, after Andy Murray, to make the last four in Melbourne since John Lloyd in 1977.
It was the first time Edmund had beaten a top-10 player, and he saved the landmark for the biggest stage of all.
Edmund can now follow in Murray's footsteps of reaching the Melbourne final, but he will have to beat Croatia's Marin Cilic, who pushed Rafael Nadal to five sets before the world No 1 succumbed to injury.
"It was fantastic," admitted Petchey. "To be able to control your nerve and control the match because he hit more winners than Dimitrov - I was super-impressed and I think everybody was.
"I really thought he had a good shot of winning because I don't think Grigor has played his best tennis here but has fought hard to get to the quarter-finals. But massive credit at the end of the day for Kyle to taking his opportunity and delivering.
"Edmund has obviously made some improvements in his game with the serve being the obvious one, but to handle the occasion and a player who has been in great form all the way through 2017 was special."
Victory ensured Edmund became only the sixth British man to reach the last four in singles at a Grand Slam in the Open era after Roger Taylor, John Lloyd, Tim Henman, Greg Rusedski and Murray.
Murray's former coach Petchey says Edmund's results may have come as a shock to many people, but he always believed the Yorkshireman was destined for great things.
"His rise doesn't come as a shock to me," he said. "He's been close all of last year. He lost a lot of tough deciding sets but he's turned those around here in Brisbane and then here in Melbourne.
"It doesn't take much when you're as good as Kyle for things to start clicking together and for me it was not a massive shock.
"I've always felt that he's a very good player, always thought that he was going to be close to the Top 10 pretty soon, and when people like Jim Courier are saying he's going to be a top 10 player, then people should be listening."
Coach Fredrik Rosengren said that bringing out the fun side of Edmund has been key to his breakthrough, and Petchey feels he has embraced the gladiatorial nature of professional tennis in recent times.
He added: "He's enjoying it because he's playing better, he's serving better, he's competing well, but he's also striking the ball great which is making things a lot more pleasurable at the end of the day.
"It's not just about having fun, it's also about being a better tennis player and that's the think Kyle has worked on. It's not just about working harder, it's about working smarter. He's always had an abundance of ability and that forehand is one of the most special shots in tennis."