Serena Williams smartly took the high road in response to questions of rival Maria Sharapova's shocking announcement of a failed drug test.

So Serena's best friend, Caroline Wozniacki, took it upon herself to slam Sharapova on behalf of Williams.

Maria Sharapova's Admission Of Failed Drug Test Portrays Different Use Of Media Than Serena Williams

"I think any time we take any medication, we double- and triple- and quadruple-check because sometimes even things like cough drops and nasal sprays can be on the [banned] list," Wozniacki said Tuesday at a news conference prior to her exhibition match with Williams at Madison Square Garden, according to ESPN. "As athletes we really always make sure there's nothing in it that is prohibited."

Much has been made of the rivalry between Williams and Sharapova which has been one-sided.

Maria Sharapova's Superior Endorsement Earnings To Serena Williams Raises Eyebrows To Serena Supporters

For each.

Serena holds a 19-2 head-to-head record against Sharapova on the court, having won 18 straight against the Russian.

Sharapova in 2014 held a 2-to-1 edge in endorsement earnings over the unquestioned No. 1 player in the world, collecting $22 million for her marketing acumen compared to Williams' $11 million.

When asked about Sharapova's failed drug test revelation, Serena spoke much more diplomatically than Wozniacki, and as sympathetically as she could.

"Most people were surprised and shocked by Maria, but at the same time, most people were happy she was up front and honest," Williams said, according to ESPN. "It showed a lot of courage about what she had done. ... That being said, it's just about taking responsibility, which she admitted she's willing to do."

She refused to take the bait to jump in on the backlash Sharapova has received since her announcement.

"When Williams was asked whether she resented competing against a doper for a decade, Williams somewhat cryptically replied: 'I'm probably not the best person to ask that question,'" ESPN reported.

"And when asked about speed in which clothing and shoe company Nike (which has contracts with both Sharapova and Williams) suspended its relationship with the Russian star, Williams dismissed the question, saying, 'I can't comment anything on that.'"

What else could Williams have said without her comments sounding like sour grapes? And Wozniacki wasn't about to let Sharapova off the hook.

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