The Germany midfielder made his competitive debut in Cardiff along with fellow new arrival James Rodriguez.
And, despite Cristiano Ronaldo scoring the two goals that secured Real's second Super Cup, Ancelotti singled out Kroos for special praise.
"Toni Kroos' performance was perfect," the coach is quoted as saying. "He was quick and clear in everything he did.
"The new players showed their quality. We're more confident than we were this time last year - and that's rubbed off on the team.
"We have many outstanding players now. It will be important to use this squad in its entirety.
"We may be entering a successful cycle. We have a squad of extraordinary quality."
Ronaldo opened the scoring by getting on the end of a superb Gareth Bale cross on the half-hour mark, before powering home a second four minutes after the interval.
And the Portuguese was also gushing in his praise for his new team-mates.
"Toni Kroos and James Rodriguez are great players," Ronaldo added. "They played well today and will be important for us."
Bizarre Jose Mourinho statement aims to pre-empt punishment after Fenerbahce boss clashes with Galatasaray counterpart
'Andy Robertson has a decision to make as a player, where you either roll your sleeves up and give someone great competition or you accept decisions and say that your time is done.' Alan Shearer on the conundrum facing Arne Slot's Liverpool
