The creative midfielder supplied the assist for the Danes' second goal as they went 2-0 in front before visitors Iceland pulled one back late on, with the friendly ending 2-1 in Denmark's favour.
Christian was substituted just after the hour mark.
Josh Onomah was also in the thick of the action, grabbing a goal and an assist to help England Under-19s see off Georgia 2-1 in the first of their European Championship elite round qualifiers in Spain.
The midfielder set up Chelsea’s Tammy Abraham to fire the Young Lions in front after eight minutes, with Josh then adding the second two minutes later. Josh played 79 minutes before being withdrawn while full-back Kyle Walker-Peters played the whole game.
In qualifying for the same competition, young midfielder Charlie Owens was forced off after only 26 minutes of Northern Ireland Under-19s' 2-1 defeat to Poland in the Netherlands.
Elsewhere, young defenders Jaden Brown and Japhet Tanganga played the full game for England Under-17s as they triumphed 3-1 over Turkey at Chesterfield in the first of their three European Championship elite round qualifiers. Samuel Shashoua was introduced as a substitute with 15 minutes remaining.
Meanwhile, Harry Winks' England Under-20s beat Canada 4-1 in a behind-closed-doors friendly, Nathan Oduwa was an unused substitute for Nigeria Under-23s as they won 1-0 away to Brazil and Erik Lamela was on the bench for Argentina in their 2-1 victory away to Chile in 2018 FIFA World Cup qualifying.
Friday night’s (March 25) action
Hugo Lloris – France international friendly away to the Netherlands