UEFA says its betting fraud monitoring system "has detected suspicious betting patterns" in Albanian club Tirana's 5-0 loss against Aalesund of Norway.
European football's governing body says it has "mandated a disciplinary inspector to further investigate the matter."
Norway's football association has said it was alerted by the national lottery, which stopped taking bets when the score reached 2-0 in the second-leg match of the second qualifying round on July 26.
Lottery officials reported unusual betting patterns from undisclosed Asian countries, including wagers that the game would end 5-0.
Aalesund, which scored four times in the second half, advanced 6-1 on aggregate.