The Italian champions have enjoyed a barnstorming start in all competitions, winning 10 straight matches and racing six points clear in the quest for an eighth straight Scudetto.
Ronaldo, 33, has been instrumental to the dominant run of results, notching four times in eight domestic appearances and figuring prominently in last month's valuable victory over Napoli.
Allegri, whose team are now on the cusp of becoming the third Serie A side to win each of their opening nine fixtures, is impressed with the ex-Real Madrid man's influence on the squad.
"Cristiano is very calm and is working well," the Bianconeri boss said. "He's been very humble and has brought even more focus and a sense of responsibility to the team.
"Besides scoring goals, which he does best, he's also great at providing assists."
Juve will look to maintain their fine form when 11th-placed Genoa visit Allianz Stadium on Saturday.
Paulo Dybala is not certain to feature after picking up a knee problem on Argentina duty, although Douglas Costa, fit after ankle and thigh injuries, is set to return from a four-match suspension for spitting.
Allegri warned his players against buying into the hype that surrounds their current run.
"Everyone says we will win all of the league and Champions League matches from here to June, but it's not like that," he said.
"Genoa will be a difficult game. At this moment, you need to return to the league with the right attitude because the game after the break is the most dangerous.
"I told the boys, this is a moment when too much positivity lowers energy. We have to keep a low profile and concentrate on work."
Allegri confirmed Giorgio Chiellini will be rested for the Genoa clash, while Sami Khedira is expected to return from a thigh issue in the Champions League trip to Manchester United on Tuesday.