Aston Villa boss Dean Smith was left bemused by the 3-0 FA Cup home defeat to Championship rivals Swansea.
Courtney Baker-Richardson opened the scoring in the second minute for the
Swans, with Nathan Dyer and Jay Fulton sealing their success with second-half strikes.
Smith said afterwards: "I never saw this defeat coming. It is the first game in which the lads have not shown enough energy, commitment or desire.
"We made a good start but Swansea then took control, looked sharper, much brighter and passed the ball with more energy. I made some changes but we didn't take our chances."
Leading goalscorer Tammy Abraham is being linked with a move to a Premier League club and missed this game and Smith said: "The difference in this game was the quality of the finishing – but I expect Tammy to be in training on Monday."
Baker-Richardson, recruited from non-league Leamington, is an action packed player who marked his debut earlier in the season by being sent off in the first five minutes against Millwall.
This contest was a much happier occasion for him as he opened the scoring early on – and Villa's much-changed team did not recover from the early setback.
The hosts' defenders were disorganised and always struggling against a nippy Swansea side who gained sweet revenge for two 1-0 league defeats at the hands of Villa this season.
Dyer and substitute Fulton wrapped up a comfortable victory for the Swans – whose manager, Graham Potter, can see a much brighter future in the forthcoming weeks.
Potter said: "It was a fine performance to get off to a great start to score within two minutes and then Erwin Mulder made a fantastic save.
"It goes to show that even in a good overall performance there is always a moment you have to survive.
"But when you look at the game over 90 minutes we generally had control and scored some good goals at the right times. As such we dampened any momentum Villa picked up in the second half.
"I am delighted with my players. Their attitude and desire to try was fantastic. We had some good quality and it was a fine win."
After scoring seven goals in two away games Potter claimed: "We have been improving of late and the performance against Villa was worthy of the win.
"I was pleased with Leroy Fer. I told him that it was his best game of the season.
"People forget that he has come back from an Achilles rupture and missed a lot of the back of last season.
"Against Villa we saw a performance level which is closer to the Leroy Fer we know. I thought it was a disciplined display."
Looking forward, he added: "For me the second half of the season is the most important.
"We have had a lot of learning in the first half (of the season). We have not had too many bad performances but now we need the results to go our way if we are to make a challenge for the top six."