Juventus manager Massimiliano Allegri has won over his egg-throwing critics in the most emphatic of styles this season.

He grabbed his second league title as a manager on Saturday following Juve's 1-0 win at Sampdoria that sealed the team's fourth straight championship and banished thoughts that he might be an unworthy follower to his beloved predecessor Antonio Conte.

Having secured the league, Allegri's team is now fighting for a treble, with the Italian Cup Final against Lazio coming up in June and even more importantly the Champions League semi-final with Real Madrid, which begins in Turin on Tuesday.

It's far more than what was expected of him.

"This scudetto feels very important because it came with a change of coach that was somewhat traumatic for us," Juve CEO Giuseppe Marotta to Sky Sport Italia.

"The first day with Allegri and the president in the car, we were greeted at the training ground by spitting, eggs and kicks."

The 47-year-old Allegri arrived at Juve after Conte shocked fans by announcing his departure in the close season before taking on the Italian national team job.

He had been sacked by AC Milan midway through the previous season after over a year and a half's humiliating speculation over his position as coach.

Allegri's stock could have hardly been any lower, and his selection for the vacant post enraged Juve fans, who had it in for their new boss due to comments he made about Juve after his Milan side were denied a potentially title-deciding win against them in 2012 thanks to the infamous Sulley Muntari "ghost goal".

"My first few days here were good. I think I only had five or six players and we lost a friendly 3-2!" he joked after Saturday's triumph.

AS Roma were everyone's hot tips for the league this year, but they fell away and have been overtaken in the league by hated local rivals Lazio, allowing Juve to stroll to their 31st title.

While Juve don't look borderline unbeatable in the league as they did under Conte, Allegri is on the verge of doing something Conte was unable to do -- take Italy's biggest club back to the top of the European game.

Should they reach the Champions League final it would only be further vindication for a manager who has turned his fortunes around in the glare of the biggest stage Italian football has to offer.

"On Tuesday we need to have the same attitude but be even better than today, because we'll have in front of us a team of amazing players to which you can't concede anything," said Allegri.

"The important thing will be going out onto the pitch knowing what we need to do against a team that can hurt you at any moment."