With Russia’s women’s gymnastics team leading by more than a point and Simone Biles abruptly out of the competition in Tuesday’s team final, it fell to Sunisa Lee, anchoring the United States on the uneven bars, to keep the Americans’ gold medal hopes alive. It was, Lee said afterward, “the most pressure I’ve ever felt in my life.” It didn’t show. The U.S. team, reeling from Biles’s withdrawal, already had two good routines in the bag, from Grace McCallum and Jordan Chiles, the latter of whom had not been scheduled to compete on bars at all and had to step in with minutes’ notice. But neither McCallum nor Chiles is a bars specialist, and their scores could not stand up to the huge numbers the Russian team was capable of. (Three team members placed in the top six on bars in the qualifying round.) Lee’s numbers could, and if the United States was to stay at all competitive for the gold medal, she had to come through. Lee, 18, scored 15.2 on bars in qualifying, second only to Nina Derwael of Belgium, who scored 15.366. And on Tuesday, with far more riding on her performance, she outdid herself and Derwael. Unlike in the qualifying round, when Lee performed a slightly less difficult backup routine after missing a connection between a transition from the high bar to the low bar and a transition back up to the high bar, she nailed her full-difficulty set. It had a difficulty value of 6.8, the highest in the world.