Milos Raonic welcomed John McEnroe back into his team box as he progressed to the last four of the ATP World Tour Finals for the first time.
McEnroe acted as a consultant for Raonic from May to August this year and was back on hand for the Canadian's crunch clash with Dominic Thiem at the end-of-season competition in London.
After a shaky start Raonic quickly found his rhythm and progressed 7-6 (7-5) 6-3 to join Novak Djokovic in the last four.
Raonic was pleased to have the seven-time grand slam champion back with his coaching team and revealed words of advice have helped his progression at the O2 Arena.
"Obviously it's a pleasure to have him there," he told a media conference. "He shares a lot of wisdom with me, a lot of his opinions.
"I respect that. I respect him a lot for all those kind of things. It was a big plus to have him there."
McEnroe will not be on hand in the latter stages, though, with Raonic confirming the American great will leave London before the semi-finals.
He added: "John I believe is already leaving tomorrow [Friday], so he won't be here for my next match. But we'll be in touch. We always are on a loose basis."
Victory over Thiem sees Raonic rise to provisional world number three - a race he is locked in with Stan Wawrinka and Kei Nishikori - and he is desperate to end 2016 just behind Andy Murray and Novak Djokovic.
"It's very big for me," he admitted. "I had a very big goal of wanting to win my first slam this year. I came up short on that. Obviously I didn't do it.
"That [finishing third] was what I had for myself as the biggest motivator after the US Open. That's what I had for myself as the biggest motivator to come here and try to heal up quickly and play.
"Right now I think I've put myself in a good situation. Obviously there's a lot that plays out tomorrow. But I've done well to give myself this opportunity. I don't know where I stand right now, but I think I've done pretty good."
Raonic finished the night meeting one of his heroes as David Beckham paid him a visit to congratulate him on his victory.