Brendan Rodgers has opened up on the tactical tweaks he implemented in the second half during Celtic's 2-2 draw with Atletico Madrid in the Champions League.
The Parkhead side led twice in the clash thanks to goals from Kyogo Furuhashi and Luis Palma but were pegged back, firstly by an Antoine Griezmann penalty and then thanks to a clinical header from Alvaro Morata.
With just under 30 minutes to go Rodgers took off Palma and replaced him with Liverpool loanee Nat Phillips and the 50-year-old explained the substitution.
Speaking to TNT Sports, he said: "It was just something I had thought about before the game. I could see at that point in the game that our backline was getting stretched because Atletico Madrid move the ball side to side really well.
"I felt we were just starting to experience some fatigue in the game maybe just because the speed of the game is not what we are used to.
"Bringing him [Phillips] in and going to a 3-5-2 with the extra body up front helped us defend when they stretched the line."
Celtic were also dealt a serious injury blow with Reo Hatate forced off against Atletico Madrid.
The Japanese midfielder couldn't continue and was substituted after just seven minutes at Parkhead.
Hatate appeared to be struggling with a hamstring issue which he pointed out to medical staff during the celebrations after Kyogo's early opener.
And just moments later Hatate required treatment from physios on the pitch before signalling he would have to come off due to the injury.
Hatate - who has been a key player for Celtic - was clearly emotional after the injury setback and looked tearful as he left the pitch before receiving encouragement from manager Brendan Rodgers.
