El Kaabi sent the visitors from Greece up 2-0 before the half hour played in Birmingham. The home side came back with goals from Ollie Watkins and Moussa Diaby, but after just under an hour El Kaabi completed the hat-trick from the penalty spot.
Afterwards, Santiago Hezze added to make it 4-2 and ensured that Villa have a difficult starting point ahead of the return match in Greece in one week. With ten minutes remaining, Douglas Luiz had the opportunity to reduce the penalty, but the Brazilian shot wide.
The loss was heavy for a Villa team that has played well in the domestic league this season. They are currently in fourth place, which gives them a place in the Champions League next season.
Hugo Vetlesen and Antonio Nusa both started on the bench for Brugge in the 2-3 away loss to Fiorentina.
Riccardo Sottil and Andrea Belotti scored for the hosts, while Hans Vanaken and Igor Thiago ensured that the doctor was equal after an hour of play. In overtime, M’Bala Nzola was the match winner.
Brugge will be without midfielder Raphael Onyedika for the next game after he picked up two yellow cards and was sent off on Thursday.
Vetlesen was replaced ten minutes before the end, while Nusa remained on the bench. The return match will be played next Wednesday.
The final has been added to Greek Athens on 29 May.
(©NTB)