Juventus captain Gianluigi Buffon admits he had "a few doubts" about his team's ability to win the Serie A title when Antonio Conte left as coach last year.
Conte stood down in July after leading Juve to three straight league titles, before he took on the role as Italy coach.
Massimiliano Allegri replaced Conte, and led his side to title success once more after a 1-0 win at Sampdoria on Saturday.
Buffon admitted there were question marks after Conte's departure.
"The Scudetti become even better as the years pass. You never get tired of winning. In fact, the older you get, the more you enjoy these triumphs," he told reporters.
"We had a few doubts when there was change in the dugout back in July, but we've demonstrated both our technical and moral merit.
"We're a group who possess a strong mentality, spirit of self-sacrifice and a will to always want more."
Buffon said the biggest challenge for his dominant team was maintaining their motivation at the top of the table.
"The 2013-14 season was close right until the end, but it was a different story this time around," he said.
"There have been some bumps along the way, that happens in years like this one and it does you some good.
"When you know you're the best, you run the risk of slacking off. Sometimes you need a kick up the backside to bring the best out of you."
