Aston Villa crashed to a chaotic 3-2 defeat on their Europa Conference League debut at Legia Warsaw.
Ernest Muci's second-half winner saw Legia pull off a deserved victory in Poland despite Unai Emery's side equalising twice.
Pawel Wszolek and Muci had twice given Legia a first-half lead only for Jhon Duran and Lucas Digne to peg them back.
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But Muci pounced six minutes into the second half and Villa couldn't recover again.
How Villa were undone
It took just two minutes for the energetic hosts to unpick their visitors with worrying simplicity. Muci sent Patryk Kun scampering down the right and he crossed for the onrushing Wszolek to fire in from eight yards.
But Villa equalised in the sixth minute when Nicolo Zaniolo's strike from 25 yards was turned onto the bar by Kacper Tobiasz and Duran reacted quickest to nod in from close range.
However, Legia regained the lead after 26 minutes when Wszolek crossed for Muci to smash in before Unai Emery's men levelled once more in the first half. John McGinn's blocked shot fell to Digne on the edge of the box and his deflected volley found the top corner.
The hosts wasted little time in going ahead again in the second half. Gual picked out Muci, who was pushed wide by Calum Chambers but still managed to squeeze his shot across Martinez and in off a post.
Emery brought on Ollie Watkins, Douglas Luiz and Moussa Diaby but Villa almost fell further behind when Gual just failed to turn in after Martinez parried Bartosz Slisz's drive.
From then there appeared little way back with Legia comfortable, seeing Jacob Ramsey's shot go wide as Villa searched in vain for a late leveller.
Emery: We could have lost with other players
Aston Villa manager Unai Emery: "I believe in our squad and our players and we could have lost this game with other players on the pitch.
"Every match away in Europe is difficult and this is a new step where we have to learn.
"We still have the possibility to react again, we are going to play another five matches. It's not a good result but we have to learn and have to understand how we're going to face the next matches and this competition.
"We have to build a squad who will play a lot of matches and we will need players in the squad to give them opportunities to play, to use their qualities.
"In the second half we started well but in one click, we conceded another opportunity and they scored a goal.
"They had a plan, they did good and we couldn't stop them in some moments."
What's next?
Aston Villa head to Stamford Bridge to face Chelsea in the Premier League on Sunday, kick-off 2pm. Their next Europa Conference League Group E fixture is at Villa Park against Zrinjski on Thursday October 5. Kick-off 8pm.
Legia Warsaw travel to AZ Alkmaar in their next Europa Conference League tie on October 5. Kick-off 8pm.