BEIJING (AP) — Andy Roddick lost to South Africa’s Kevin Anderson 4-6, 5-7 in the first round of the China Open on Monday, a defeat the sixth-seeded American called “unacceptable.” Roddick then walked out of his news conference when asked about any retirement plans.

Roddick managed to handle Anderson’s huge serve but struggled with his own and was broken in the seventh game to go one set down. The second set brought more of the same. While Roddick evened things up at 5-5, Anderson’s momentum carried him through.

“If I break twice and don’t win a set that says my serve isn’t on,” Roddick said. “It’s unacceptable.”

The 29-year-old Roddick, winner of the 2003 U.S. Open, has dropped in the rankings to 15th after several early round losses this year.

Roddick was asked after the match how close he might be to retiring, and he rolled his eyes before replying: “I think you should retire.” He then got up and left the news conference to a round of applause.

Roddick took to Twitter later to dispute that he left early.

“About this whole ‘walked out of a press conference’ thing. Moderator announced that it was last question before my retirement response,” Roddick posted.

On the women’s side, top-ranked Caroline Wozniacki rallied from a set down to beat Lucie Hradecka of the Czech Republic 3-6, 6-0, 7-5.