Momentous happenings in the early stages of grand slams tend to mean bad news for the top seeds and Li Na was the one to fall on her sword and take an unwanted place in tennis history.

As the first Chinese player to win a grand slam, she is well used to setting records but yesterday, as she slunk out of Paris as a round-one loser, it was of the wrong kind. Slapping the ball anywhere but in the court, the No.2 seed was beaten 7-5, 3-6, 6-1 by France's Kristina Mladenovic, ranked 103. Following the exit of Stanislas Wawrinka the previous evening, it is the first time the two champions at a grand slam have gone out in the first round of the following grand slam.

Mladenovic, who was ranked in the top 40 last summer, played superbly but Li, as frank as ever, said she probably would have lost to whoever she was up against. "Nobody say if you are No. 2 in the world you have to win all the matches," she said. "This is tennis. Everyone who comes to the court has a chance to win the match.

"I think it doesn't matter who plays today against me, I would always lose the match today because I don't think she was putting a lot of pressure on me. Today I just gave it away."

As the Australian Open champion, much was expected of Li, not least since she won her first grand slam title in Paris in 2011. But right from the start she was off her game, spraying the ball this way and that and eventually she paid the price.

"The problem is myself," she continued. "Even during the match, I didn't think what I should do, I didn't follow the game plan and even when I was standing up the court, in my mind I didn't have any idea how to play the match."

Heather Watson held her nerve to beat the world No.63 Barbora Zahlavova-Strycova from the Czech Republic 6-3, 6-4. It was Watson's first grand slam win since last year's Australian Open, thanks to a combination of glandular fever and injury. But the 22-year-old is now assured of a ranking somewhere in the 70s, putting her on course to regain her British No.1 ranking. In round two, she will play No.4 seed Simona Halep of Romania, who crushed Alisa Kleybanova 6-0, 6-2.

Caroline Wozniacki, the former world No.1, was beaten in three sets by Yanina Wickmayer, but the Dane then had to fend off questions about her recent split from Rory McIlroy, who ended their relationship two days after their wedding invitations had been sent out. Wozniacki read a statement at the start of her press conference thanking everyone for their kind words, but did admit things had been hard.

"It came as a bit of a shock, she said," in rather understated fashion.