Rafael Nadal suffered a setback in Rome ahead of the French Open. Getty

While Rafael Nadal remains the favorite to win the French Open, he may have been given an indication Friday that the road to the title might be a tougher task than once thought. At the Italian Open in Rome, Dominic Thiem defeated the clay-court specialist in the quarterfinals 6-4 6-3.

Nadal had won the tournament seven times and the final nine times but has failed to capture the tournament since 2013. The Spaniard, who saw his 17-match winning streak snapped, admitted that Thiem got the best of him in a match that saw Nadal convert just 32 percent of his first-serve points.

"He was very aggressive, very strong," Nadal said of Thiem. "He played very well, didn’t miss much and was able to push me back."

Nadal, who turns 31 on June 3, is a 10/11 favorite to win at Roland Garros, followed by Novak Djokovic (10/3), Thiem (10/1), Andy Murray (14/1) and Stan Wawrinka (14/1), according to Oddschecker. Absent from the odds is Swiss legend Roger Federer, who decided to skip the tournament to focus on grass and hard-court tournaments.

After some struggles in 2015 and 2016, Nadal has performed well this year. He has a 36-6 record and has won three titles. Currently ranked No. 4, Nadal even reached the Australian Open final, a tournament he has won just once in his illustrious career.

Nadal's success or failure at the Italian Open doesn't always relate to how he performs at the French Open. In 2008, he lost in the second round to Juan Carlos Ferrero and then went on to win the French Open without surrendering a set. Nadal also failed to win the Italian Open in 2011 and 2014, only to go on to win the French Open in both years.

The last time Nadal won in Paris was in 2014. Arguably the greatest clay-court player in tennis history, Nadal will be seeking his 10th French Open title next week.