British star Emma Raducanu is the focus of an injury scare ahead of the Australian Open after retiring with an apparent ankle strain in her second-round match at the ASB Classic on Thursday. (More Tennis News)

The 2021 U.S. Open champion took only 22 minutes to sweep the first set 6-0 against Slovakian qualifier Viktoria Kusmova but faltered and lost the second set 7-5.

Raducanu summoned the trainer courtside to heavily strap her left ankle in a long injury break.

The 20-year-old Raducanu attempted to play on but was not able to complete the first point of the third set. She was tearful when she came to the net and acknowledged she could not continue.

Raducanu was marked as one of tennis' hottest stars when she won at Flushing Meadows. 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.?

Venus Williams blew a 5-3 last-set lead in a match, which stretched over nearly seven hours because of rain in losing to Zhu Lin of China 3-6, 6-2, 7-5.

The 42-year-old Williams fought through every moment of the second-round match which began after noon and ended near 7 p.m., which began outdoors and ended indoors, and which contained 13 service breaks before finally tipping in favor of Zhu in the last few games.

Seven-time Grand Slam champion 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 had the upper hand early when she took out a first set which included five service breaks in 43 minutes. She was 2-1 down when the first rain break of more than an hour occurred, but returned to break Zhu's serve twice and take the set.

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

Williams broke first for 2-1 in the third set and extended that advantage to 5-3, coming within reach of a quarterfinal spot. But Zhu broke back, held serve and broke Williams again to advance.

Williams left the court after her sixth appearance in Auckland to no applause, but also to no suggestion her career is nearer to an end.

It was not great,” Williams said. “Definitely tough. 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 her 6-4, 6-4 win over compatriot Sofia Kenin, the 2020 Australian Open champion.

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.

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