RIO DE JANEIRO — It looks as if Usain Bolt has a new rival. Or perhaps a new sidekick.

Bolt, who lit up Rio with his third straight Olympic gold in the 100 meters this week, was coasting to a semifinal victory in the 200 Wednesday when he felt someone on his right side challenging him. A quick glance showed him to be Andre De Grasse, the young Canadian who took bronze in the 100, and he was threatening to pass him.

Bolt, the 29-year-old two-time defending champion in the 200, flashed a huge smile, turned on the jets, and edged De Grasse at the finish line. Once there, he turned and wagged a finger De Grasse’s way, as if to say, “Not yet.”

The two embraced, shared a laugh, and walked back to the locker room together. No hard feelings.

“I don’t think he expected me to do that,” the 21-year-old De Grasse told reporters after the race. “I had to push him a little bit, you know, see what he has left in the tank.”

Bolt said: “He was supposed to slow down. I said: ‘What are you doing? It’s a semifinal.’ But I think he wanted to push me.”

De Grasse’s challenge adds a level of excitement to Thursday night’s 200 final. The American Justin Gatlin failed to qualify, leaving the young Canadian to be Bolt’s foil.

How to watch: The race is scheduled for 9:30 p.m., Eastern time, on NBC.