Premier League Swansea City fell victims to the first major giant-killing of the FA Cup third round on Sunday when they lost 3-2 away to League Two (fourth tier) side Oxford United.
There were more than 50 league positions between the clubs but Oxford came from behind to lead 3-1 after Ecuador international Jefferson Montero had put Swansea ahead.
Liam Sercombe equalised from a penalty just before half-time and two goals in 10 minutes soon after the interval from Kemar Roofe put the home side in sight of victory.
Bafetimbi Gomis pulled one back for the Welsh club, who had made 10 changes from their last Premier League game, but Oxford held on.
“I thought the performance was outstanding, it was always going to be a difficult game against a Premier League side,” their manager Michael Appleton told BBC Sport.
“I don’t want to give Kemar Roofe too much praise but he’s done ever so well this year — we’re very used to seeing goals like his first one today in many games.
“This is reward for everyone at the football club but it’s really important to gain promotion and if we can improve on the squad it will stand us in good stead.”
Oxford,a top-flight team 30 years ago before dropping back into non-League football from 2006-10, are third in League Two, with the top three in May due to go up.
Roofe, who signed for them from West Bromwich Albion in the close-season after a successful loan period, felt the triumph was down to his team’s efforts rather than any lack of application by Swansea.
“I don’t think they underestimated us, we were just on our game,” he said.
Alan Curtis, recently appointed Swansea manager until the end of the season, said his much-changed team had been “poor” for the first hour of the game.
“We made changes and there was a certain amount of rustiness but I am disappointed,” he told reporters.
“The team we picked was strong enough to win, but all credit to Oxford. They were the better team and deserved to win.
“The league was always going to be the priority but we wanted a cup run and to get some momentum going. It’s a huge setback for the club.
“We’re going to have to lift everyone for our next game.”
That match is a crucial Premier League fixture against fellow-strugglers Sunderland on Wednesday.
Sunderland are bottom but one with 15 points and Swansea are only two places ahead of them on 19 points.