Sixth-seed Donna Vekic of Croatia was the first seeded player to be knocked out of the BMW Malaysian Open Tuesday after she lost 6-3, 4-6, 6-2 to American Bethanie Mattek-Sands in the first round.
The 16-year-old, who is ranked world number 93 and only turned professional in September, was outmanoeuvred in the match against an opponent who is better known for her doubles play.
The 27-year-old Mattek-Sands, who is world number 197, arrived in Kuala Lumpur to participate in the rain-lashed tournament after winning a doubles title with India's Sania Mirza in Dubai last week.
"It was a good match. My opponent played well. It was quite hard at first as I had never played her before, but she is young and has lots of... potential," she said, admitting that her experience made the difference.
"I had to step up a notch in the third set and played more aggressive with big serves. At the end it was a well fought match, and I am happy to win," added Mattek-Sands, who has 12 WTA doubles titles to her name.
The American, who is playing in Malaysia for the first time, said she was still adapting to the Southeast Asian country's humidity.
Rain marred the first two days of play, putting the tournament well behind schedule with six matches postponed to Wednesday.
Top seed and former world number one Caroline Wozniacki of Denmark is also scheduled to play Wednesday.
"The heat is tough but everyone has to play in the same humidity. We just have to fight it out and be stronger," Mattek-Sands said.
"I came here not knowing what to expect but all my fellow players that I asked said it is the 'hottest' tournament of the year."
Mattek-Sands will now face either Marta Sirotkina of Russia or Duan Yingying of China in the second round.
Joining Mattek-Sands in that round are Patricia Mayr of Austria, Karolina Pliskova of the Czech Republic and fifth-seed Misaki Doi of Japan.
Doi had no trouble against Italian Alberta Brianti, breezing past her opponent 6-2, 6-3.