The 23-year-old, who moved to the Stade Louis II in January, has suffered with ankle problems in recent years.
However, he believes that a full pre-season with the Ligue 1 newcomers has stood him in good stead and helped him amass five goals in four league games.
"It has been two years since I had a complete pre-season," he told the Ligue 1 website. "The doctors and physiotherapists here at Monaco have managed to fix my ankle, which has handicapped me for two years.
"Thanks to God, everything is going well now. I'm at 100 per cent of my capacities, which is essential given the way I play."
Riviere has started two of Monaco's league fixtures this season, being introduced as a substitute in the other two, helping move Monaco top of the standings.
Claudio Ranieri's men are yet to lose in the league this season and Riviere is delighted with how things are working out.
"Coming into the season, I had some pretty lofty ambitions, and I didn't think I would reach them so soon," said Riviere, who is challenging Radamel Falcao for a forward spot.
"This (ankle problem) was my first injury as a professional player and no-one seemed to be able to find a solution.
"At Saint-Etienne and Toulouse, the doctors did their best but the pain wouldn't go away. But when I arrived at Monaco, the medical staff solved the problem, and I have to tip my hat to them.
"Without them, I wouldn't be where I am right now."
