AUCKLAND, New Zealand — Emma Raducanu blamed slippery indoor courts for an ankle injury which forced her to withdraw from the ASB Bank Tennis Classic on Thursday, less than two weeks before the start of the Australian Open.

The 2021 US Open champion was in tears after retiring in the third set of her second-round match against Slovakian qualifier Viktoria Kusmova.

The British player slipped late in the second set and then summoned the trainer who heavily strapped her left ankle during a lengthy injury break. The 20-year-old Radacanu attempted to continue and was serving in the first game of the third set when she tearfully indicated she could not play on.

Matches at the Auckland WTA Tour event were moved indoors Thursday for the second straight day because of heavy rain.

"It's difficult to take," Raducanu said. "I've put a lot of physical work in the last few months and I've been feeling good and optimistic. So to be stopped by a freak injury, rolling an ankle, is pretty disappointing. In the first week as well, I thought I was playing some pretty decent tennis. The courts were incredibly slick, like very slippery. So to be honest it's not a surprise that this happens to someone. It's out of my control and after a very long day of waiting around."

Raducanu was marked as one of tennis' up-and-coming stars when she won at Flushing Meadows, but her career since has been dogged by injuries. She retired from matches four times in 2022 and most recently has had to contend with a wrist injury.

Also Thursday, Venus Williams couldn't convert a 5-3 lead in the third set as she lost to Zhu Lin of China 3-6, 6-2, 7-5 in a match which stretched over nearly seven hours because of rain.

The 42-year-old Williams fought through every moment of the second-round match which began outdoors after noon and ended indoors near 7 p.m., and which contained 13 service breaks.

Williams, starting her 30th year on the WTA Tour, won her first tour match in nearly two years when she beat Katie Volynets on Monday in the first round of the Auckland tournament. She played only four matches in 2022 and was hoping to progress to the second round of a tournament for the first time since 2019.

Williams was 2-1 down in the first set when the first rain break of more than an hour occurred but returned to break Zhu's serve twice and take a 1-0 lead.

Zhu led 4-2 in the second set when the rain returned and forced the players indoors onto a court without spectators. Zhu held serve for 5-2 then broke Williams again to level the match.

Williams broke first for 2-1 in the third set and extended that advantage to 5-3. But Zhu broke back, held serve and broke Williams again to advance.

Williams later questioned the decision to start the match outdoors when rain was imminent and delay in moving indoors.

"Being the first match is like being a guinea pig," Williams said. "It was not great. I've played a lot of matches in my life and I've played through some intense delays but it was definitely like two separate matches.

"Outside, it was really tough. It was rainy, windy. It was tennis but it was more about surviving instead of playing great. Indoors, it was completely different but I got to hit a lot of balls so that's important." Top-seeded American Coco Gauff will face Zhu in the quarterfinals after a 6-4, 6-4 win over compatriot Sofia Kenin, the 2020 Australian Open champion.

The seventh-ranked Gauff also had to play indoors and beat Kenin in just under 90 minutes, leveling their head-to-head record after Kenin beat Gauff en route to the Australian Open title.

Seventh-seeded Danka Kovinic beat former champion Lauren Davis 4-6, 6-3, 6-2 and qualifier Rebeka Masarova beat Anna Blinkova 6-1, 6-4.

                                                                                                             AP