World No 3 Murray stunned Nadal 6-3 6-2 to win the Madrid Open on Sunday, his first Masters title on clay and a second clay crown in a week.
It was also the Scot’s first victory over the Spaniard on clay in seven attempts, but he believes Nadal will still be the man to beat come Roland Garros at the end of the month.
“I think there were periods of the match where he played like he usually does, but there were also periods where he made more mistakes,” Murray said.
“On that court (in Paris) he has only ever lost one match, so when the French Open comes round he’ll be one of the favourites. It is maybe closer than it’s been in previous years, but I wouldn’t write him off.”
“He showed enough this week to suggest that with two good weeks of work and good results in Rome (at next week’s Italian Open), he can go all the way at Roland Garros.”
Sunday’s defeat means Nadal will drop to seventh in the latest world rankings, the first time he has been out of the top five in 10 years.
The 14-time Grand Slam champion is also defending 600 ranking points in Rome having made last year’s final.