The French outfit had gotten a 3-1 win over Javi Calleja's men in the reverse fixture and despite having to battle in a cagey affair at Estadio de la Cerámica, the Burkina Faso international popped up with a late match-winning goal.
In the 85th minute, Nabil Fekir, through on goal and with only Sergio Asenjo to beat, unselfishly square the ball for Traore, who converted into an unguarded net.
The Yellow Submarines finished the game a man less after defender Juame Costa was dismissed in the 78th minute.
The forward has now scored 11 goals in 28 games in all competitions and will be looking to continue his form in the next round of the competition.