Would it be better for both teams to drop two points? Or would a Milan victory suit, if Celtic's main ambition is to finish third and remain in European competition?
In the end, Mario Balotelli decided for them, rescuing a point for the visitors with an injury-time penalty to level the scores at 1-1. He has a reputation for being one of the world's deadliest spot-kick takers - although he missed for the first time in his career this month at home to Napoli - and the Italian lived up to his billing. The decision to award the penalty four minutes into stoppage time was controversial; Mike van der Hoorn, the Ajax substitute, had looked more the victim than the aggressor when he tussled with Balotelli in the area.
It would have been an unlikely win for Ajax. Despite being on top in the first half, the home side were pinned back for large stretches of the second, after a transformed Milan had emerged from the dressing room. Riccardo Montolivo came close with a close-range flick, which drew a super stop from Jasper Cillessen, and a Balotelli free kick deflected off the wall and onto the roof of the net.
Nevertheless, Ajax it was who took the lead. Stefano Denswil rose above the Milan defence to thump home Lasse Schoene's corner. Once the goal went in, the game burst into life. Balotelli, though, was to strike a killer blow.
Milan are now second in Group H on four points, two behind leaders Barcelona. Ajax are third having picked up their first point of the campaign after losing 4-0 to Barcelona in their opening fixture. Two games with Celtic await the Dutch side, in which both their fates will surely be decided.