Sharapova's 'courage' draws Serena's salute

Serena Williams says Maria Sharapova "showed a lot of courage" in taking responsibility for her failed drug test.

On Monday, the Russian star revealed she tested positive the day she lost to Williams in the Australian Open quarterfinals in January.

At a media conference on Tuesday to promote an exhibition at Madison Square Garden, Williams did not want to talk about beating an opponent with a banned substance in her system.