Serena: Sharapova showed 'courage' in admitting failed drug test

Serena Williams said she was "surprised and shocked" as anyone to hear the news that Maria Sharapova had tested positive for a banned substance the day the Russian tennis star lost to Williams at the Australian Open quarterfinals in January. 

Speaking at a media conference prior to Tuesday's BNP Paribas Showdown exhibition event against good friend Caroline Wozniacki, the 21-time Grand Slam champion lauded Sharapova for taking responsibility for the failed drug test. 

"I think most people were happy she was upfront and very honest and showed a lot of courage to admit to what she had done and what she had neglected to look at in terms of the list at the end of the year," Williams said.

On Monday, Sharapova announced she tagged for using meldonium —€” a blood flow-promoting drug that she said she had been taking for 10 years for various health issues —€” which was included on the updated banned substances list for 2016 for the first time.

While she has provisionally been suspended since Saturday, Sharapova could also face a long ban from the International Tennis Federation, which may keep her from competing at the Rio 2016 Summer Olympics. 

"Just hope for the best for everybody in that situation," Williams said, though the Nike endorser refused to comment on the athletics company's decision to suspend its relationship with Sharapova.  

"She showed a lot of courage and a lot of heart. I think she's always shown courage and heart in everything she's done, and this is no different," Williams said.