For Roger Federer, the menace did not come from the other side of the net.
After dispatching Colombian Alejandro Falla in straight sets, the 17-time Grand Slam winner was about to leave center court Sunday when a young man ran down the stands and made his way to the Swiss star unhindered. The fan brazenly put his hand across his shoulder to try and get a selfie with him.
Federer looked surprised, then a bit uncomfortable as he seemed to question with a hand gesture why the security guards did not intervene. One of them finally grabbed the man and took him away.
While there was no ill intent from this fan, the incident raised concerns about security at the event and clearly riled Federer.
"I'm not happy about it. Obviously not one second I'm happy about it," Federer said, adding that he received an apology from tournament director Gilbert Ysern. "It happened yesterday in the practice, too. I think it's true for all players that you have to feel safe when we play, feel safe on the courts. It shouldn't happen too often. It's happened twice in two days and also in 2009 during the final. I think people should react more quickly. First, it should never happen."
That was the only incident in an otherwise smooth start to the French Open for Federer, who advanced to the second round with a 6-3, 6-3, 6-4 win over Falla.
Facing a player who pushed him to five sets at Wimbledon five years ago, the 2009 champion was never threatened this time, extending his unbeaten run against the 111th-ranked Falla to 8-0.
On a sunny first day of play at Roland Garros, last year's runner-up Simona Halep also advanced in straight sets in the women's draw.
Federer put Falla under pressure in the eighth game of the first set, breaking for a 5-3 lead when the Colombian could not handle a good backhand return. Federer shouted "come on" after earning a set point in his next service game and closed it out when Falla sent a backhand into the net.
Federer's flashy outfit, with pink shorts and a lilac shirt, was almost as eye-catching as some of the shots the former top-ranked player produced. The 17-time Grand Slam winner broke again for a 2-1 lead in the second set following a game in which he left Falla stranded with a perfectly hit defensive lob.
Federer wrapped up the second set with another break in the ninth game. At 4-3 down in the third set, Falla called a trainer to get his right thigh massaged. The Colombian held his next serve but could not prevent Federer from breaking him in the 10th game as the Swiss unleashed a forehand attack that he returned wide.
On the women's side, the third-seeded Halep hit an ace on match point to beat Russian Evegenia Rodina 7-5, 6-4, while ninth-seeded Ekaterina Markova breezed past American wild card Louisa Chirico 6-4, 6-2.
Halep made a big breakthrough at the French Open last year, losing in final to Maria Sharapova after not conceding a set in her previous matches.
Halep, who said she is stronger than last year both physically and mentally, is bidding to become the first Romanian to win a Grand Slam title since Virginia Ruzici at the French Open in 1978.
"I have stronger body and I have improved a lot in my game," she said. "Serve is better, so I feel more confident now with my game."
Up againt Halep in the second round will be veteran Mirjana Lucic-Baroni, who defeated American Lauren Davis 6-3, 3-6, 6-3. Lucic-Baroni, who won her first match at Roland Garros since 2002, upset Halep at the U.S. Open last year.
"I have not good memories from that match," Halep said. "I just was blocked and I couldn't hit the ball."
On paper, the 33-year-old Federer has a relatively easy draw until the fourth round, where he could meet 13th-seeded Gael Monfil before a potential quarterfinal with his Davis Cup teammate Stan Wawrinka, who beat Marsel Ilhan 6-3, 6-2, 6-3.
Federer, who achieved a career Grand Slam by winning the French Open in 2009 after three runner-up finish, has not made it to the final on the Parisian clay since 2011. He lost in the fourth round last year but has been playing excellent tennis recently and has a 26-5 record in 2015. On clay, he lost in final in Rome after claiming an 85th career title in Istanbul.
Among the seeded players to advance to the second round Sunday were also No. 19 Roberto Bautista Agut and No. 22 Philipp Kohlschreiber. The first seeded player to bow out was No. 25 Ivo Karlovic, who lost 7-6 (5), 6-4, 6-4 to Marcos Baghdatis.