Europa League: Progres Niederkorn 1-0 Cardiff Met
Mayron de Almeida's second-half goal condemned Cardiff Met to defeat on their European debut away to Progres Niederkorn of Luxembourg.
But the Archers will be confident of overturning the deficit in the return leg on Thursday, 4 July.
Met's home leg will be played at Cardiff International Athletics Stadium at Leckwith rather than Cyncoed campus.
Christian Edwards' side are the first British men's university club side to qualify for Europe.
The winners will face Cork City in the first qualifying round.
Their second qualifying-round opponents could be Rangers, if Steven Gerrard's side overcome Prishtina or St Joseph's in the first qualifying round.
Progres Niederkorn qualified for the Europa League after finishing fourth in the Luxembourg National Division last season.
They caused a stunning upset in 2017 to knock out Rangers with a 2-0 second leg victory.
Cardiff Met manager Christian Edwards said:
"It was nearly mission accomplished, it was nearly a perfect performance for me.
"We knew the opposition would be dominate with the ball, we knew they'd try and probe through central areas and we set up to try and not let that happen.
"It took a good old fashioned Welsh Premier League cross into the box for them to score, but it's half-time and we've kept the tie alive."
Progres Niederkorn: Flauss, Skenderovic, Vogel, de Almeida, Muratovic, Bah, Thill, Laterza, Hall, Karayer, Matias Marques. Subs: Czekanowiz, Cervellera, Bastos, Correia Santos, Adrien Ferino, Borges, Shala.
Cardiff Met Uni: Fuller, Rees, Lewis, Woolridge, Edwards, Baker, Corsby, McCarthy, Eliot Evans, William, Spencer. Subs: Lang, Lam, Williams, Morgan, Black, Parker, Phillips.
Referee: Luis Teixeira (Portugal).