A combination of injury, loss of form and being shifted between scrum-half and fly-half meant that the 31-year-old has not been at his effervescent best for Toulon this season.
But with two fly-half starts in a row, a loss against Clermont followed by a win against his boyhood club Toulouse, Michalak appears to finally be hitting his stride.
And Mignoni, his backs coach at Toulon, is hoping there is still more to come ahead of a France summer tour to Australia.
"Fred mixed the good with the not so good (against Toulouse)," said Mignoni, who won 28 caps for France.
"It was not an easy match, he did not have many options with what was going on around him to do more.
"That was his second match in a row at fly-half and he managed to do some great things.
"Fred is a very positive guy, I am not at all surprised that he has come back to his best."