The 20-year-old had only scored one Europa League goal in his 13 appearnces in the competition so far this season, but picked the perfect time to double his tally for the campaign.
With 53 minutes of Thursday's second leg at the Red Bull Arena Salzburg, the youngster gave his side the boost they needed as looked to dump the side that they took four points off in the group stage out of the ocmpetition.
Haidara picked the ball up 15 yards inside the Marseille half and embarked on a twinkle-toed run which took him past four visiting defenders before prodding the ball beyond Yohann Pele from just inside the box.
The goal left Salzburg needing one more without reply to force extra time or two to progress.