Sofia Kenin admitted she was given a stern test by Kirsten Flipkens before the Belgian was forced to abandon their tussle at the Abu Dhabi Women's Tennis Open.

With a month to go before Kenin begins the defence of her Australian Open title, the American world number four was fighting to avoid a second-round exit to an experienced opponent.

Flipkens took the first set 7-5 and trailed 5-4 in the second, a break down, when an injury to her left ankle caused her to retire from the match.

A run of three consecutive games and 12 unanswered points from Flipkens had seen the 34-year-old former Wimbledon semi-finalist snatch the opener.

Kenin was turning the contest around in the second set and the top seed admitted she was "a little bit upset" to see Flipkens suffer when injury struck.

"We're good friends and that's not something you like to see," Kenin said, quoted on the WTA website. "I just hope [Flipkens] can have a speedy recovery and get ready for Australia.

"She played a really good match. It was the third time we’ve played each other, and it was a really solid match from both of us. This is not the way I wanted to win."

Aryna Sabalenka could be a player to fear at Melbourne Park in February, as the world number 10 made it 11 consecutive match wins by fending off Australian Ajla Tomljanovic 7-5 6-4.

Sabalenka finished off the 2020 season with titles in Ostrava and Linz so the Belarusian is looking for a hat-trick of tournament triumphs.

Tunisian Ons Jabeur scored a 5-7 6-3 6-2 victory against Kateryna Bondarenko of Ukraine to reach the last-16 stage, and she faces Sabalenka next.

Jabeur won on the only previous occasion she and Sabalenka have met, securing a three-set win in round three of the delayed 2020 French Open.