LONDON — Usain Bolt set the stage for his grand farewell, powering down the finishing straight Saturday to qualify Jamaica for the 4x100-meter relay final at the world championships.

Fittingly, he will face Justin Gatlin and the US in the final chapter of his unparalleled career.

Both nations won their heats early Saturday, though the US relay squad got the baton around with more aplomb than Jamaica, which had to rely on Bolt to clinch victory.

And Bolt relished the adulation at the 60,000-capacity Olympic Stadium.

“They’ve been outstanding so far, and continue to surprise me and give me energy,” Bolt said.

For the best part of the past decade, though, Bolt has been 100 percent reliable in getting relay gold for the island nation. The last time Jamaica lost a world championship final was in Bolt’s rookie year in 2007, when he ran the second leg and only took silver behind the Americans.

Ever since, Bolt has flaunted his power at the end of every major championship, getting the third gold medal for himself and sometimes another world record for Jamaica.

This year, however, he only got bronze in the 100 behind Gatlin. And the result in the relay is no longer a foregone conclusion.

The US, with Gatlin running the second leg, won the first heat in a world leading time of 37.70 seconds. The Americans beat Britain and Japan, both of which also qualified.

“My team did a great job,” said Gatlin, the oldest of the squad at 35. “They’re thinking and acting like veterans and I’m proud of them.”

Christian Coleman took silver in the 100 ahead of Bolt and it gave the US team an added boost.

“Having the gold and silver medal on the same relay team, which hasn’t been done in a long time, it gives us kind of a confidence booster that the speed can get around the track,” Gatlin said.

Bolt stepped out on the track for the second heat, and the Jamaicans needed him. Trailing when he got the baton on the anchor leg, Bolt powered away, quickly swept past his rivals and had time to look to his right before crossing in 37.95 seconds.

In the women’s heats, both nations are also through.

Allyson Felix stayed in line to become the athlete with the most medals in world championships history when she helped the American relay team qualify.

Running the second leg, Felix and her teammates crossed first in a season’s leading time of 41.84 seconds, beating Britain and Switzerland. They also advanced to the final.

In the second heat, Germany beat two-time defending champion Jamaica to qualify along with Brazil.

The Netherlands, with 200-meter champion Dafne Schippers running the second leg, qualified on time.

Felix has won 14 medals at the world championships and can move up to 16 if she runs the 4x400 relay and the United States wins medals in both events.

In the decathlon, two-time world champion Trey Hardee of the United States hit the third hurdle and clattered into the next one during the 110-meter hurdles to end his medal chances.

In the first of five events on the final day of the two-day competition, Kevin Mayer of France set a third personal record to easily stay atop the standings with 5,485 points. Rico Freimuth of Germany was in second place with 5,377 points, while Damian Warner of Canada had the fastest time in the hurdles of 13.63 seconds to move into third. — AP