Experience triumphed over youth in the Miami Open semi-finals where a pair of veterans held off talented Canadian teenagers whose time to shine will have to wait.

Denis Shapovalov, 19, and 18-year-old Felix Auger-Aliassime saw their exuberant runs in the tournament halted by their older counterparts but not before showcasing their talent that bodes well for the future.

For Shapovalov, his matchup with 20-times Grand Slam singles champion Federer was something he had long dreamed of.

"It's surreal, being on the court against him," Shapovalov told reporters after losing in straight sets.

"Obviously I wasn't trying to focus on the fact that it's Roger on the other side. I was just trying to play as good as I can, and he did a good job today. I'm just going to try to learn from this and move forward."

Shapovalov had practised with a Federer, 37, on a couple of occasions, but stepping into a competitive arena against him was a learning experience and one that could serve him well.

Shapovalov, who defeated Rafa Nadal nearly two years ago in Montreal, said he could see a change of guard coming in tennis.

"Yeah, there is definitely a lot of talent coming in," Shapovalov told the Daily Express. "It's just that point in the ATP, you know, you still have kind of the legends, you know, Rog, Rafa, still there on top, but you have a lot of newcomers with talent kind of gunning for them."

Auger-Aliassime could be one of those newcomers after becoming the youngest men's semi-finalist in the Miami Open's 35-year history.

The young standout had chances to serve out for wins in both sets of his 7-6(3) 7-6(4) defeat to American 33-year-old John Isner but was ultimately undone by costly double faults.

"The biggest lesson was to stay in the present and believe in yourself, because you can always dig deep and find resources within yourself," Auger-Aliassime said of his run.

"So I think that's a huge lesson to not give up, stay calm, and just work every day."

"His (Shapovalov) results and mine are pushing each other. I think, yeah, a lot of belief, a lot of positive things happening, and I think it's just pushing us."