Coach Bernard Laporte's men have won only one match in the tournament so far, thrashing Scotland 38-3 at the Stade de France on February 23.
Their last two matches with Italy and Wales are now crucial in terms of building confidence ahead of their tours of Argentina and New Zealand and the World Cup this autumn.
"Of course a defeat against Italy would plunge us into doubt, it would simply be catastrophic," Maso said in L'Equipe.
"Last season, the last three matches against England, Scotland and Ireland had allowed us to progress gradually and we should not question everything now.
"We should remember that we lost to England while scoring three tries and that the defeat to Ireland was very close."
Laporte, meanwhile, has yet to recover from the setback in Ireland.
"The team has lost much of what used to be its strength, that is to say unity and discipline," he added.
Olivier Magne, however, refuses to give up on his team's hopes of moving forward.
"Whatever we may think, we are progressing," he said. "We are confident about our quality of game and our collective unity is gradually improving."