Normally, an away match in the British Isles, in a rainy Celtic Park, is a tough task with a pulsating atmosphere in the stands.
But without an audience, Celtic are not the same team.
Tonight Milan came to visit and with Zlatan Ibrahimovic as the central point, they went up in an early lead.
Rade Krunic nodded in 1-0 and shortly afterwards Brahim Diaz extended to 2-0 in an attack that "Ibra" directed through a smart pass in the deep.
Hauge goal scorer
Ibrahimovic was substituted in the 66th minute and Celtic got in touch when Mohamed Elyonoussi, cousin of former AIK player Tarik, put 1-2 on the nod.
Milan kept out, however, and in extra time, substitute Jens Petter Hauge, 21, ran free and shaved his first goal for the club.
It is no wonder that the goal was his first.
Hauge was recruited from Bodö / Glimt three weeks ago after netting against Milan.
Extends the suite
The victory means that Milan builds on their loss-free suite, which now extends just over seven months back and amounts to 21 straight matches.
The team has not had such a long suite since a period between October 1995 and March 1996, when they went 27 straight without a loss.
With big star Ibrahimovic on the field, they have played 25 matches this year - and they include 16 wins, six draws and two losses.