MELBOURNE, Australia (AP) -- At several moments during her match, Luksika Kumkhum said her heart shook. She told herself not to look at the stands. She'd never seen such a huge tennis stadium.
Before long, the crowd at the 5,000-seat Margaret Court Arena was cheering for the speedy, unheralded Thai player, who made a name for herself at the Australian Open on Monday by eliminating former Wimbledon champion Petra Kvitova, 6-2, 1-6, 6-4 in a first-round upset.
It marked a number of firsts for the 20-year-old Thai, who is ranked 88th and had never before played a top 10 player and hadn't expected to win. Before exiting the court, she thanked the crowd with a display of Thai graciousness by bowing with palms pressed together to all four sides of the arena.
''Today is a great day,'' she said during an on-court interview, openly stunned by her victory. ''Thank you very much,'' she said, and then repeated herself in Thai: ''Khup khun kha.''
She was then ushered into Melbourne Park's main press conference room, another first, then told media that although she's Thailand's top tennis player, nobody recognizes her in the streets of Bangkok.
Luksika grew up in Chanthaburi province in eastern Thailand. She started playing tennis early because her father was a coach.
He's the one who taught Luksika her grinding two-handed backhand and her more unusual two-handed forehand, she said. Inspired by former Thai tour players Paradorn Srichaphan and her idol Tamarine Tanasugarn, Kumkhum turned professional at 19.
This was her second Grand Slam after reaching the second round in Melbourne last year, on a side court.
Stepping onto Margaret Court, the tournament's third show court, made her ''heart shake.''
''It made me really nervous, so I tried to look only at the court. I didn't look up,'' she said during an interview in Thai. ''I just looked at the court and focused on the ball. I didn't think I was going to win.''
She wore a Buddhist pendant around her neck for luck. It also helped that Kvitova made 40 unforced errors and was serving poorly.
''Unfortunately, I didn't play well,'' said the No. 6-seeded Kvitova. Asked what went wrong, she said, ''Everything.''
It was Kvitova's first loss in the opening round of a Grand Slam since the 2011 U.S. Open, months after she won the title at Wimbledon.
Luksika faces Germany's Mona Barthel in the second round Wednesday.
VENUS LOSES IN SINLGES: Venus Williams has suffered illness and injuries in recent years but doesn't want to talk about her weaknesses. She wants to focus on her tennis.
''I love tennis. It's fun,'' said the seven-time Grand Slam winner after losing her first-round match to No. 22 Ekaterina Makarova, 2-6, 6-4, 6-4.
Williams hasn't reached a Grand Slam quarterfinal since 2010 and is ranked 37th.
Williams revealed several years ago that she suffers from Sjogren's syndrome, an energy-sapping autoimmune disease.
''The last 12 months, I have had issues, but this year I definitely am looking forward to, you know, having a good run and feeling well.''
Health is a factor that all professional athletes have to deal with, she said.
''So I don't think I'm any different from anyone else,'' said Williams, who at 33 was the second-oldest player at the singles draw.
She's not done in Melbourne. Williams returns to the court later this week to try to win her 14th Grand Slam doubles trophy with her sister, Serena.
LOST COUNT: So, exactly how many match points did Madison Keys waste before winning?
There were so many, she lost count.
''Basically, there was a lot,'' the American teen laughed. ''I can't tell you how many there were, I'm just really happy I closed it out on the last one.''
There were six - five match points in the second set and another in the third before Keys finally beat Patricia Mayr-Achleitner of Austria 6-2, 6-7 (8), 9-7.
''This is one of those matches where you're just happy you got through it,'' said the power-hitting, huge-serving 18-year-old, who is seen as one of the rising stars in American tennis.
Now ranked 36th, Keys had a breakthrough season in 2013, which she started 137th. She reached the third rounds at last year's Australian Open, which she entered as a wild card, and Wimbledon. Keys faces Zheng Jie of China in the second round.
Keys was one of five American women who advanced to the second round Monday. The others were No. 1 Serena Williams, Irina Falconi, Alison Riske and Lauren Davis.
Associated Press Writer Justin Bergman contributed to this report.