Rafa Nadal laid down a marker for anyone looking to deprive him of a fourth consecutive French Open title. 

The champion of the last three years at Roland Garros lost just four games in a straight sets demolition of MacKenzie McDonald.

Nadal's numbers in themselves are frightening. Wednesday's win was his 95th in 97 matches on the red clay of Paris. He struck just 15 unforced errors, hit 31 winners and won 55 per cent of his first-serve return points.

"I am very happy," Nadal said on-court after the match.

"I am just trying my best every single day. I am working hard in every practice to try to be better and better in every match.

"Today was not that cold, so that's the main thing. Not that cold, the conditions are not that bad."

Nadal's next potential victim is world no.74, Stefano Travaglia. The Italian beat the unseeded Kei Nishikori in five sets.

US Open champion Dominic Thiem also disposed of an American in three sets. The third seed beat Jack Sock to set up a meeting with the dangerous Casper Ruud.

"I'm still a little bit on the happy wave of New York," the Austrian said afterwards.

"Of course, at one point I'm going to get super tired. I guess all the tension and focus on Roland-Garros, it's hiding still the tiredness and everything. I hope I can push it as far as I can."

Thiem's Flushing Meadows final opponent - Alexander Zverev - was taken the distance by Pierre-Hugues Herbert, before taking the fifth 6-4.

There was a 150th career Grand Slam win for Stan Wawrinka, who beat Dominik Koepfer in four sets. Next up for the Swiss is 20-year old wild card Hugo Gaston.

The 6'10" American John Isner was beaten in five sets by his younger compatriot Sebastien Korda - son of 1992 finalist Petr Korda.