Brendan Rodgers claimed there were a "lot of positives" to take from Celtic's 2-0 Europa League defeat to RB Leipzig in the Red Bull Arena on Thursday night.
Hampered by injuries or suspension to several of his top players, the Northern Irishman brought in Cristian Gamboa, Jozo Simunovic, Eboue Kouassi, Ryan Christie and Lewis Morgan.
But after an encouraging start to the Group B match, the visitors were punished for defensive lapses, first on the half-hour mark by striker Matheus Cunha and again four minutes later by attacker Bruma.
The defeat left the Scottish champions in third place with three points from nine, with leaders Salzburg on nine and RB Leipzig second with six.
But Hoops boss Rodgers said: "There were a lot of positives from the game. We started very, very well, imposed our style on the game.
"After 25 minutes Ralf (Rangnick, RB Leipzig boss) changed the system to match up with our diamond.
"I felt we were finding the spaces well and getting in good positions. We had a great chance with Odsonne Edouard after seven minutes. It was a big chance at this level.
"And we had a period of 15 minutes after that when we made a mistake from a cross coming in and at this level you get punished for that.
"It knocked us a bit for five to 10 minutes and they got the second but we regrouped again, changed our shape for the second half and we found a better comfort in defending the spaces.
"We had a chance late on. If we get it to 2-1, it makes it an interesting finish but we didn't quite manage to get the goal.
"Some of our play was very good but key moments in the game we have to defend better and unfortunately we didn't do that."
Rodgers hailed the quintet that were brought into the Celtic side in Germany.
"The players that came in tonight did fantastic," he said.
"They haven't been playing a great deal and would get great experience from that. Lewis Morgan came in and gave everything in the game.
"Christie, Kouassi, these boys came in and gave everything and showed moments of quality.
"It's unfortunate we have so many injuries but it's not the fault of the players. They gave absolutely everything."