It would have been a treat to see James and Merritt duel at full strength on Monday. But even though James made his gold medal run look easy, winning by more than half a second, it has been a challenging year.

While many of his rivals in the 400 were able to focus exclusively on race preparation, James had to juggle training and full-time studies at Alabama, where he was on a student visa and thus obligated to follow a full-time course load even though he had already turned professional and was no longer running for the university’s track team.

In March, at the world indoor championships in Istanbul, he yawned repeatedly in the starting blocks and finished last in the final in an outside lane. His coach, Harvey Glance, a former Olympic sprinter from the United States, and his agent, Renaldo Nehemiah, once the world’s best 110-meter hurdler, both expressed concern that he was wearing down and also expressed concern that commitments to appearances in Grenada were an additional strain.

But James looked fresh and alert Monday night, and he is now the only sprinter from outside the United States to break the 44-second barrier. At 19, he will now face increased scrutiny as to whether he can threaten Michael Johnson’s 13-year-old world record of 43.18 seconds.

“Obviously he’s been a huge thing for our sport and our event, and obviously everyone wants to reach that high level at some point,” James said, referring to Johnson. “I’m just focused on being the best I can be. I don’t try to be like Michael Johnson, because if I try to do that, every time I fail it’s going to be a disappointment.”

It has already been another fine Olympics for the Caribbean. Shelly-Ann Fraser-Pryce and Usain Bolt repeated as gold medalists in the 100 meters. Bolt received his gold medal Monday night not long before James took to the track, and there was an unplanned fireworks display in the stands of Olympic Stadium as Bolt did a standing broad jump onto the podium and hundreds of flash bulbs went off in random order as fans captured images of Bolt from afar.