Harmony Tan looked composed enough during her wild upset of Serena Williams in the first round of Wimbledon Tuesday, but if you ask her, she would tell you otherwise.

The 24-year-old from France, who was playing in her first Wimbledon main draw, said after her staggering tiebreak victory that she was originally frightened when she saw who she was facing.

“When I saw the draw I was really scared,” Tan told the BBC after the match, per the Daily Mail. “Because it’s Serena Williams, she’s a legend. I thought if I could win one or two games it was really good for me.”

Her nerves didn’t show, however, and after Serena battled back in the first set, Tan closed the door on her, taking the first set with some impressive strokes.

Williams won the second set handily and had a chance to close Tan out with a 5-4 lead in the third, but the Frenchwoman broke the 23-time Grand Slam champion to even the score and eventually send it to a tiebreak. After a gassed Serena took a 4-0 lead in the tiebreaker, Tan battled back and won, 10-7.

It was Serena’s first singles match since last year’s Wimbledon, where she also was forced out of the first round, that time due to injury. She told reporters she hopes to play at the US Open.

Tan, meanwhile, moves to the second round, where she will face No. 32-ranked Sara Sorribes Tormo.