Tennis: Serena Williams has know won more Grand Slam titles than any other woman, after defeating her sister, Venus, in straight sets. Names like men’s finalist and 17-time grand slam winner Roger Federer and Australian legend Rod Laver are often thrown up, but Williams – who won her 23rd grand slam title at the Australian Open on Saturday night – said that she, Martina Navratilova and Steffi Graf all deserve to be top of the discussion.