Two former Wimbledon champions advanced to the second round on Tuesday as both Rafael Nadal and Novak Djokovic won in straight sets.

Fresh off of his Roland Garros title, Nadal took to the grass for the first time and showed no ill effects from the change of surface as he cruised past Dudi Sela 6-3, 6-3, 6-2.

Early, Sela went toe-to-toe with the Spaniard on the grass surface getting to tough balls and striking with a purpose. But that didn’t last long as Nadal seized control of the match, serving well and forcing Sela into untimely errors.

Despite having not played on the surface in a year, Nadal looked comfortable on the grass, striking the ball from his wheelhouse for much of the match, dictating the points.

“After a while without playing on grass, it's very important to start with a straight victory,” said Nadal, who last won the Wimbledon championship in 2010.

The world no. 1 will face Mikhail Kukushkin next, in the second round.

Meanwhile, three-time Wimbledon champion Djokovic continued to return to form with an impressive 6-3, 6-1, 6-2 win over Tennys Sandgren.

The American had no answer for the Serb’s game who made things look routine. Djokovic appeared confident in all aspects of his attack. His groundstrokes were crisp and his serve effective as he controlled play and forced Sandgren into 35 unforced errors.

“I thought it was overall quite a solid match,” said Djokovic. “I don't think Tennys has played a great match. I think he made a lot of errors. Just the third set, a couple games he changed up the tactics pretty well. I don't think he was at his best. At the same time, you know, I made him play a lot on his service games. I thought I served accurately.”

After a quarterfinal run at the Australian Open, Sandgren shot up the rankings but on Tuesday, he never looked comfortable against the former world no. 1 on the Wimbledon grass.

Djokovic will face Horacio Zeballos in the second round.

Elsewhere, 7th-seeded Dominic Thiem was forced to retire against Marcos Baghdatis, in their first-round match. The French Open runner-up was down 6-4, 7-5, 2-0 when he had to quit. Thiem looked to be in pain and received a medical timeout for treatment on his back but had to retire early in the third set.