Sweden ended the United States' 44-game unbeaten run with a 3-0 win in the Olympics group stage on Wednesday and Megan Rapinoe hailed them as one of the best European sides ever.
Strikes either side of the half-time whistle from Stina Blackstenius and a goal by Lina Hurtig proved the difference as Sweden claimed a famous triumph over their heavyweight rivals, who they defeated on penalties in the 2016 quarter-finals.
The world champions enjoyed a two-year spell without losing before the Group G opener but will quickly have to bounce back if they are to follow up their France 2019 success with Olympic gold.
Rapinoe found it hard to defend the USA's performance as she credited Sweden's hard-working display.
"We did not play a very good game and that is to take nothing away from Sweden, they played a great game," the attacking midfielder said after the match.
"This is the highest level and these are the best teams in the world. Sweden are one of the best ever in Europe and the world. If we don't play well we don’t win these games.
"We want to be a lot better, we played a bit tight and hurt ourselves a lot. You can't say one thing specifically.
"I can't remember the last time we gave up a goal, so to give up three is not great but we know what we need to do to win these games, get out of the group and go from there."
Head coach Vlatko Andonovski refused to panic and is keen to see a response against New Zealand on Saturday.
"It has put us in a big hole and we are the only ones who can get ourselves out of it," he said. "It is not going to be easy. We have to get good results in the next two games, but I know this team will not give up.
"I don’t remember this team losing 3-0 in recent history so it is a bit of a shock, but everyone is positive. We still have games ahead of us. We have got to bounce back. We have to forget this game and focus on the next one."
In contrast, Blackstenius, whose brace sealed a remarkable victory, spoke glowingly of her team, who were without Chelsea captain Magdalena Eriksson for the win.
"I'm very happy about the goals - of course I'm happy to score. The team helped me very much and I think I could have scored at least two more but I don't want to focus on that. I'm just happy and proud of the team", the forward said.
“We developed our game and our play. It's very good and we have so much quality in every player. Every player is also very different from the other. We have so many players that can do good stuff and as a team we are very good. Every player is very happy about going very attacking."
Hedvig Lindahl, though, maintained that Sweden's win was simply a starting point and that Peter Gerhardsson's side had not achieved what they had come to the Games for yet.
"It's just the first group game, we haven't won anything yet. We need to keep going," the veteran goalkeeper said. "If you have one high into lows in the group then this means nothing. But to win against the USA, it's something we can take some confidence from.
"You can go very far in a tournament even if you lose to the USA or whoever you play in the first game, so I don't know how much it means, but we showed the world and ourselves that we can play good against a team like the US and any team."