A pair of goals from Swedish forward Stina Blackstenius spelled catastrophe for the United States, as they suffered a shock 3-0 defeat in their Olympics opener.
Fifth-ranked Sweden put the pressure on almost immediately with three shots in the first eight minutes, as the four-time Olympic gold medalists showed little sign of the stellar unbeaten run they have enjoyed since 2019.
Forward Stina Blackstenius converted in the 25th minute, rocketing a header past US keeper Alyssa Naeher with an assist from Sofia Jakobsson.
Midfielder Rose Lavelle nearly equalised with a header in minute 45 off a corner kick from Christen Press but hit the post.
The addition of veteran midfielder Julie Ertz did little to revive the US in the second half, as Blackstenius again scored in the 54th minute.
The match was personal for Team USA: The Swedes knocked the four-time World Cup winners out of the tournament on penalties in the quarter-finals in 2016.
But their much hoped-for revenge in front of 48,000 empty seats inside the Tokyo Stadium was not to be, as forward Christen Press missed a wide open net at close range midway through the second half.
Swedish midfielder Lina Hurtig then heaped on more pain with a clinical header to give her side a three-goal cushion a minute later.
The Rio defeat marked the US team's earliest exit in Olympic history, after previously reaching the final of every edition of the Games since 1996, when the women's event was introduced.
The United States next face New Zealand in the group stage, while Sweden play Australia, both on Saturday.
Brazil's Marta became the first woman footballer to score in five consecutive Olympic Games when she netted twice in a 5-0 thrashing of China at the Miyagi Stadium in Rifu.
Marta, widely regarded as the greatest women's footballer of all time with a record five World Player of the Year awards, scored her first Olympic goal in Athens in 2004 and, following Wednesday's brace, now has 12 Games strikes.
The 35-year-old opened the scoring in the Group F clash in the ninth minute when she arrived late in the box and pounced on a rebound. Debinha made it 2-0 in the 22nd minute.
Marta added her second with a low drive from a tight angle in the 74th minute before forward Andressa converted an 82nd-minute penalty to leave China reeling.
Beatriz completed the rout in the 89th minute after latching on to a low cross to beat the goalkeeper with a first-time effort.
Ellen White's double gave dominant Great Britain a comfortable 2-0 win over Chile in their opening match at the Tokyo Olympics.
The Manchester City striker struck in each half to give GB a winning start to their campaign in Japan.
That Hege Riise's side failed to add to the scoreline owed much to their own profligacy and desperate, last-ditch, defending from Chile.
They now face the hosts in Sapporo on Saturday before playing Canada in Kashima to complete Group E next Tuesday.