Mahamadou Sangare struck a hat-trick for City, with a Melvin Gomes own goal and Ryan McAidoo's effort also on the scoresheet for the visitors.
“I thought we started well, started on the front foot, got an early goal. And I thought mentality-wise we were in a really good place,” Wilkinson told City's website afterwards.
“We conceded a disappointing goal in terms of higher up we lost a duel, and then fair play to them, their technical quality on the transition was really high.
“They’re the moments you want to try stuff out when you play this level. And again in the second half the goals we conceded were a bit disappointing. I thought for the large majority of the game we were good, and winning games away from home in Europe is hard.
“You come to Monaco and think of the Academy and the players they have produced in the last 10, 20 years, is top. And you know there is good players on the pitch today so they are going to hurt you at times.
“Lots of positives, and if we can tighten up on a few of the areas we want to I think we’ve got a really exciting team.”