The midfielder side-footed home the equaliser from 16 yards on 71 minutes after City's Stevan Jovetic opened the scoring in the second half. That was his sixth goal for Denmark in his 52nd cap. The Danes won it thanks to Viktor Fischer's penalty four minutes from time.
Christian and Denmark now prepare for a big Euro 2016 qualifier at home to Serbia on Saturday.
Kyle Walker-Peters drew praise from coach Neil Dewsnip after England Under-18s beat Russia 2-0 in the first of back-to-back friendlies in Moscow on Monday.
The full-back - whose performances earned a call for our post-season tour of Malaysia and Australia - played the full 90 minutes as goals from Newcastle Adam Armstrong and Fulham's Patrick Roberts saw the Young Lions home.
"The back five were absolutely outstanding," Dewsnip told TheFA.com.
"I thought Freddie (Woodman, goalkeeper, Newcastle) contributed with a super save at the end. If that had gone in then the last few minutes would have been real nervous.
"The two centre-backs, Dael (Fry, Boro) and Tosin (Adarabioyo, City), that is as good as I've seen them play and I'm very impressed. And then Kyle and Callum (Connolly, Everton) just got better and better at this level. Those five deserve huge credit."