ST. LOUIS — The list of possible U.S. women’s gymnastics teams could be jumbled and picked at random, and the group could still head to Tokyo favored to rack up medals and win the team gold. That’s the expectation for any team led by Simone Biles, the world’s best gymnast, who will soon head to Japan and be in position to earn even more titles than she already has.

Biles’s second Olympic berth wasn’t official until Sunday night, but she had essentially already locked up her spot thanks to nearly a decade of dominance. Sunisa Lee and Jordan Chiles have seemed poised all season to join Biles on the four-member Olympic team, and their performances here at the U.S. Olympic trials only strengthened their cases. Then there was the fourth spot, and the selection committee had to choose. Grace McCallum, an 18-year-old from Minnesota, earned the nod.

McCallum finished fourth after two days of competition at the Dome at America’s Center. But those results weren’t enough to solidify an Olympic berth. Only the top two finishers, Biles and Lee, left the competition floor and entered the waiting room with guaranteed trips to Japan. The others had to wait. McCallum had only a narrow edge over MyKayla Skinner — three-tenths of a point based on the cumulative score of eight routines. And Skinner, an Olympic alternate in 2016, had the advantage of a vault that could contend for an individual medal.

But U.S. high performance coordinator Tom Forster said the selection committee wanted to preserve the “integrity of competition.” A team with Skinner would have scored higher in a final than one with McCallum, but because the difference was small, the committee decided to go with the top four all-arounders.

Rather than running through hypotheticals and simulations, Forster said, “the better thing to do is let the athletes select themselves.” And in his mind, that meant naming the four highest-ranked gymnasts in the all-around standings to the Olympic team.

When the gymnasts emerged from the tunnel, wearing new Team USA sweatsuits and overcome with emotion, McCallum stood with the four-member team. But Skinner, 24, will still go to Tokyo. She was named as one of the two individual athletes who will compete, joining Jade Carey, who had already clinched her spot. The six athletes, and a crew of alternates, celebrated as confetti rained down from the ceiling. Fireworks exploded behind them. And in a few weeks, these new faces of U.S. women’s gymnastics will travel to Tokyo with Biles as their leader.

“It probably won’t hit me until tomorrow,” said Chiles, 20, who felt confident in her chances during the wait. “I’m in shock. I think I probably blacked out or something.”

Since the 2016 Rio de Janeiro Games, Lee, 18, has emerged as one of Team USA’s top all-arounders behind Biles, including winning three medals at the world championships in 2019. Lee excels on uneven bars with a routine that combines difficult release elements. Her score on that event alone — a 15.300 on the first night of the trials Friday, then a 14.900 on Sunday — is enough to significantly lift the U.S. team total.

This weekend, Lee earned the best two-day combined score on both bars and balance beam. Her all-around total Sunday led the field, even ahead of Biles. Lee didn’t realize that until her coaches mentioned it, and “I know it probably won’t happen again,” she said. But the result gives her confidence.

Biles fell on beam and had a couple of minor mistakes on the other apparatuses. She wasn’t thrilled with that showing, but she is still the best gymnast in the world and had more than a two-point advantage on Lee in the two-day total, finishing at 118.098 to Lee’s 115.832.

Biles, 24, is undefeated in the all-around since 2013, so she looks at herself as her own competition. She delivered a spectacular all-around performance on the first night of competition, but after those mistakes Sunday, she said, “Simone night one kicked Simone night two’s butt.” When Sunday’s meet ended, Biles still felt relief and “a lot more emotions going into it because of everything I’ve been through,” she said. “It’s been a long journey.”

Chiles, who switched clubs two years ago to train alongside Biles, has thrived with a new, healthy training environment. Now she is one of the nation’s most consistent elite gymnasts. Since the Winter Cup in February, Chiles hasn’t made a major mistake, hitting 24 consecutive routines. When Chiles capped her evening Sunday with a solid floor routine, she buried her head in her hands. Her spot hadn’t been secured because she finished just third, but she had done plenty — both at this competition and over the past few months.

Carey entered the trials with her Olympic berth already secured, the only gymnast who had that luxury. She chose years ago to pursue an individual spot in Tokyo through the apparatus World Cup series. She might have been in contention for the four-member team had she not chosen that route, but she essentially decided to earn a guaranteed trip instead of shooting for a spot on a team that is heavily favored to win the gold medal in Tokyo.

Riley McCusker, who trains with Carey in Phoenix, entered as a favorite to earn the other individual spot because of her medal potential on bars. She hasn’t performed on any other apparatus since suffering an ankle injury last month. At the trials, McCusker scored a 14.800 on Friday, the second-highest mark in the field, but she fell on her first skill Sunday. McCusker’s Olympic hopes slid into jeopardy, and Skinner earned that spot instead.

“When it comes down to it, MyKayla also has world-class start values and execution on vault,” Forster said. “And she hit.”

Team USA would have had a strong team in Tokyo regardless of who Forster and the selection committee chose. All of the gymnasts vying for the fourth spot probably could have contributed to a team favored to win gold. Others with the potential to reach the finals on particular apparatuses did not make the squad.

But the group heading to Tokyo is filled with star power and potential. Team USA has Biles, and now everyone joining her will receive their first taste of the Summer Games with massive expectations surrounding them.

“I just feel really relieved,” Lee said. “I’m still very emotional. It’s so surreal to say that I’m an Olympian now.”

Updates from Sunday’s trials...