The Argentine - who, alongside team-mate Neymar, has been shortlisted for the 2015 FIFA Ballon d'Or - suffered a knee injury in September and only made his return in the 4-0 triumph over Real Madrid on November 21.
Barca lost just one of their nine fixtures in all competitions without Messi, as Neymar and Luis Suarez proved crucial to Luis Enrique's side.
However, Spain international Busquets feels the entire team reached a new level following the loss of their talisman.
"Without Messi, all the players have taken a step forward," Busquets told TV3.
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"It was good to see that we were able to win without him, we played well and we won games.
"He's the best player in the world and our star. It's a pleasure to play with [Messi, Neymar and Suarez], not only because of their quality, but how they help the team in defence."
Barca sit four points clear of Atletico Madrid at the top of La Liga and, according to Busquets, they are hoping to secure another treble this term.
"I admire Luis Enrique's desire to work and improve," he said of the head coach.
"We're a very good team who have a great future.
"We have the ambition to win another treble, but it'll be very difficult."