Serena Williams out with knee, plans on Australian Open

World number one Serena Williams has played down her recent injury scare and insists she is on track for the Australian Open.

She had already missed the US’s opening Hopman Cup tie due to inflammation of her left knee before attempting to play against Wolfe.

World No 1 Serena Williams had to pull out of her first match of the season with a knee injury – just two weeks before the Australian Open.

Williams, who has won 21 Grand Slam singles titles, sat out the tail-end of last season, saying she needed “time to heal” after narrowly missing out on a rare calendar-year Grand Slam. “(Because of) inflammation in my knee I need to rest”. Williams trained again briefly on Tuesday and took to the court against Wolfe (nee Gajdosova), but appeared very restricted in her movements especially on her left side.

Hopman Cup tournament director Paul Kilderry said Williams reported feeling pain in her knee on Sunday.

Williams has been replaced by Vicky Duval in the US team for the last Group A match against the Czech Republic on Thursday.

Williams’ near-perfect 2015 ended on a lacklustre note after a shock defeat in the US Open semi-finals, but Cibulkova said that was indicative of the pressure she was under to complete the Grand Slam. “I’ve put a lot of hard work over the off-season and it has paid off”.

Meanwhile, Maria Sharapova and Simona Halep have withdrawn from the Brisbane International to make it a worrying start to the season for tennis’ leading women.

Murray who led Britain to their first Davis Cup triumph in 79 years just over a month ago, took under an hour to seal the victory 6-2, 6-2.

Fifth-seeded USA player Sloane Stephens won against Slovakia’s Polona Hercog in match scores of 6-3, 6-3, as well as Irina Falconi beating out number six seeded Coco Vandeweghe in match scores of 5-7, 6-4, and 6-3.

When Duval was just seven years old, she was held hostage at gunpoint by robbers at her aunt’s house in Port-au-Prince.

The Briton eventually succumbed 6-3, 5-7, 6-3.

Venus, 35, the tournament top seed and defending champion, was beaten 7-6, 3-6, 3-6 by 18-year-old Russian Daria Kasatkina, while Ivanovic went down in straight sets to British qualifier Naomi Broady 7-5, 6-4.