Only one WTA player has an opportunity to capture a calendar-year grand slam in 2018 – Caroline Wozniacki. The Danish star broke through for her maiden major title earlier in the season in Melbourne. On Monday, she began her quest to win a second major and return to world no. 1 as she defeated American Danielle Collins, 7-6,6-1.

Wozniacki was tested in the first set by the up-and-coming American but after winning a first set tiebreak, she cruised in the second set as the errors began to mount for Collins.

The 27-year-old said she has a different approach at Roland Garros after her accomplishment in Australia.

“It’s a much more relaxed approach (that I have now),” she said. “Being No.1 and winning a Grand Slam are two of the goals I always dreamt of and to achieve both of those this year was incredible. I’m just so happy to be here having won the first Grand Slam of the year already.”

She will face Georgina García Pérez in the second round.

Novak Djokovic successfully began his French Open with a 6-3, 6-4, 6-4 win over Rogerio Dutra Silva on Monday. It was a routine straight-sets win for the 12-time grand slam champion who continues to return to form after an injury that resulted in a fall outside of the top-20 in the rankings.

The 2016 French Open Champion entered Roland Garros with some confidence after a semifinal run in Rome. And while it was not a textbook win for the Serb, it was businesslike. At times, Djokovic showed some glimpses of the game that propelled him to world number one and finished the match with a strong third set overall.

Meanwhile, it was a difficult day for the 2015 French Open champion, Stan Wawrinka. Last year’s runner-up fell in the first round to Guillermo Garcia-Lopez 6-2, 3-6, 4-6, 7-6, 6-3. With the loss, the Swiss will fall outside of the top-250 in the world.

At 33-years-of-age, some critics have questioned whether Wawrinka can return to the form that led him to 3 grand slam singles titles (French Open 2015, Australian Open 2014, US Open 2016) but the veteran kept things in perspective after the loss.

When asked about working back up the rankings, Wawrinka responded, “Well, you start to win matches. ‘Simple as that,” he said. “You practice well, and you get your level back and you win matches, and in a few months, you’re back up to your level if you play well. That’s as simple as that. You know, when you’re out on the tour because of injury, that’s for sure your ranking will drop no matter what, because you didn’t play.”

He acknowledged that the road would not be easy, “For sure, I’m going to require some wildcards. But again, if I have to play some challenger, I have no problem with that.”

Wawrinka missed significant time due to a knee injury and is still working himself back into form.

It was a difficult draw for the 23-seed, who faced a player who can grind on the clay surface, which was evident in the three-and-a-half-hour match.

Garcia-Lopez will advance to face Karen Khachanov in the second round.

Elsewhere, Victoria Azarenka, the two-time grand slam champion, and 2013 French Open semifinalist, found her stay in Paris a short one as she fell to Kateřina Siniaková 7-5, 7-5. It was the first major appearance for the former world no. 1 since Wimbledon of last year.

Early in the match, Siniakova played inspired tennis riding a strong serve and she found an opening as Azarenka served at 5-6 in the first set. The Czech broke serve and took the first set. But, as has been displayed before, Azarenka would fight back gaining an early service break in the second set. But to the credit of the 22-year-old, she would battle to get back on serve and then, the opposite of the first set, both players struggled to hold serve as the pair traded breaks. But it was Siniakova who settled down to take the second set and the topsy-turvy match.

38 unforced errors were the undoing of Azarenka who played aggressively but not consistently.

After a nice day of weather, the rains halted play late in the day with several matches underway. Action will resume in the morning from Paris.