Sipping champagne following Marseille's 3-1 home win over Stade Rennes, Dassier paid tribute to coach Didier Deschamps, who joined last year and helped OM clinch the League Cup and the Ligue 1 title, their first silverware since the 1993 Champions League.
"His strength was to keep some key players from last season," Dassier told reporters with a hoarse voice.
Niang scored Marseille's second on Wednesday before Argentine midfielder Lucho Gonzalez wrapped up the win.
"We needed some experienced players," said Deschamps, who was the last OM captain to lift the national trophy in 1992.
"I needed everybody to understand that they had to work for the squad, not just for themselves and I sometimes had to break their balls," Deschamps, wearing the club's tracksuit, said with a smile.
"I am very happy but I am not going to dance on the table. I'm a bad dancer anyway."
"Margarita (the wife of the late Louis-Dreyfus and new owner) is not gonna write me a 50 million euro check," he said. "We have to build with what we have.
"Not winning a title for so long was not normal for Marseille," he added.
"But now we have to cement our status as a great French club and do better in the Champions League, that's our goal."
"Next season will be tougher," warned Deschamps.
"We need to be patient now because it's after the greatest victories that you make the biggest mistakes."
