Montpellier captain Alessandro Stoica hailed his side's Parker Pen Shield triumph as one of the most important wins in the club's history.
The French side claimed silverware in their first season in Europe after beating Viadana at Parma's Stadio Sergio Lanfranchi thanks to tries from Sebastien Buada, Laurent Arbo and Christian Chemin.
And Italian international centre Stoica, who won the Shield with Castres last season, was full of praise for his team's efforts as they headed home for a well deserved rest.
"This is a very important result for us and it symbolises a big step forward for the club. This has been a very big season for us as it was the first time we have been in the French Championship and in Europe and we have finished well," said Stoica.
"We have secured our place in the Top 16 for next season and claimed a European trophy. Beating a very tough Viadana team is a great reward for all the hard work we have put in over the last 10 months and hopefully now we can progress next season."
The visitors found themselves six points adrift in the opening exchanges as Casper Steyn landed two early penalties for Viadana, but the French side fought back to lead 12-9 at the interval.
Tries from Sebastien Buada and Laurent Arbo, the first converted by David Bortolussi, put Montpellier into the lead, but a third Steyn penalty on the stroke of half-time cut the gap to three points at the break.
Sylvain Jouve and Steyn then swopped penalties in the third quarter before a try by lock John Daniell on the hour tipped the scales firmly in Montpellier's favour. Jouve added the extras and then kicked another penalty to stretch his side's lead to 13 points.
But full back Steyn's one-man show for Viadana wasn't over and when he converted his own try seven minutes from time the game was back in the melting pot. Viadana threw everything they had at their visitors, but Montpellier kept their cool and managed to hold onto their lead.
"We are very disappointed because we really wanted to win this game, not just for ourselves but also for Italian rugby," said Viadana's Director of rugby, Franco Bernini.
"We kept the score close in the first half but our defence was poor at the start of the second and we did not seem to have the confidence to change things in attack when we needed points.
"But we were up against a very strong and organised team and we will learn from this wonderful experience."
HT: 12-9 Attendance: 2,553
Montpellier: Tries - S Buada, L Arbo, C Chemin; Pens - D Burtolussi, S Jouve;
Cons - D Burtolussi, S Jouve.
Viadana: Try - C Steyn; Pens - C Steyn 4; Con - C Steyn.
Man of the match: S Buada (Montpellier)
Referee: D Pearson (England)