TOKYO — The Americans’ efforts at the Tokyo Games have produced results that might be the envy of the world but have fallen short of their recent lofty standards. The U.S. Olympic team is in danger of losing the gold medal race in a Summer Olympics for the first time since 2008.

Poised to win about 106 medals based on the final rounds of competition through Sunday, it will slip back to roughly on par with the London Games in 2012, when it won 104 medals. The team won a record 121 medals in 2016 in Rio de Janeiro, and 46 of them were gold, two fewer than the mark the Chinese set for gold medals in 2008 in Beijing.

The blame for the shortfall can be spread around. The track team won 32 medals in Rio but had just 22 heading into the final night. American men have not won a gold medal in the speed events that have long been their bread and butter.

The U.S. women’s soccer team, the two-time defending World Cup champion, settled for a bronze medal. Simone Biles, the greatest gymnast ever, missed the bulk of the meet as she battled mental stress. American rowers failed to make the Olympic podium for the first time since 2008.

With the slip in American dominance, several other countries, notably Japan and China, have surged.

Japan, with 51 medals through Friday night, surged past its tally of 41 medals, including 12 gold, won in Rio. In these Games, it has 24 gold. After eight years of backtracking, China’s Olympic sports machine has returned: With 36 golds compared with 31 for the United States, the Chinese have a shot at winning the gold medal race for the first time since 2008.