Two of the three goals came from the penalty spot as the Nigerian international took his competition total this season to six with the Turkish club moving up from 16th to ninth place in the standings with nine points from four games.

Ajax, who have been European champions four times, remain rooted at the bottom of the 36-team table without a point.

Osimhen stooped to head home Leroy Sane’s cross in the 59th minute to open the scoring and then tucked away a 66th-minute penalty after a clumsy handball by defender Youri Baas.

Ajax gave away a second spot kick when Gerald Alders, on his European debut, inadvertently handled the ball in the box while trying to block a shot, with Osimhen stroking home the resultant penalty in the 78th minute.

Ajax came closest to a goal after an error from Galatasaray goalkeeper Ugurcan Cakir allowed Mika Godts a shot at an empty net but he missed out on the opportunity.