Tennis: Top WTA players hit by injuries ahead of Australian Open

Serena Williams, Maria Sharapova and Simona Halep all have fitness issues ahead of this month's Australian Open, the first Grand Slam tournament of the season. All three players have pulled out of tournaments at the start of the year. World number one Serena Williams suffered a knee injury and retired during a match against Australia's Jarmila Wolfe in the Hopman Cup. Maria Sharapova has pulled out of the Brisbane International tournament with an arm injury while world number two Simona Halep also decided to pull out of that event due to an inflamed Achilles tendon. Serena Williams said she should be able to play in Thursday's Hopman Cup tie against the Czech Republic and then at the Australian Open. "I just have some inflammation that's been going away very slowly," she said. "It needs a little rest, a little treatment." Sharapova said about her injury: "I hurt my forearm in practice a couple days ago and need to precautionary withdraw with the Australian Open starting soon." The Australian Open kicks off on 18 January, here are the odds at Bet365 for the top five favourites to win the title: Serena Williams - 3.25 Victoria Azarenka - 7.00 Simona Halep - 9.00 Maria Sharapova - 9.00 Garbine Muguruza - 12.00