What Venus Williams knew during the final against her sister Serena that the world didn't.

When Serena Williams won the 2017 Australian Open women’s singles final, she was pregnant with daughter Olympia.

Serena won her 23rd title by beating her sister Venus Williams 6-4 6-4 in the final.

However at the time, her pregnancy was hidden. The world didn’t find out about her pregnancy until three months later, when she made the announcement by sharing a baby bump picture on Snapchat in April.

Nearly two years later, Serena has shared in an interview with Mamamia that Venus was in a “really uncomfortable position” during the match.

After the final, both sisters were typically gracious: Venus said she wasn’t disappointed to lose because she enjoyed seeing the Williams’ name on the trophy.

Serena told the crowd her sister was the reason she was so successful.

“She is my inspiration, she is the only reason I am standing here today and the only reason that the Williams sisters exist. Thank you Venus for inspiring me to be the best player that I could be and inspire me to work hard.”

Now, in an interview with Mia Freedman on the No Filter podcast, the athlete said Venus knew of her pregnancy before they faced off in the final.

Listen to Mia’s full conversation with Serena Williams below, or subscribe to the No Filter podcast here.

When asked if her sister went easy on her because of it, Serena said she hoped not.

“I think it was a very difficult position for her to be in, to be honest. You know your really close friend is going through something and you have to play them, it’s just a really uncomfortable position for her to be in.”

Serena said she played differently after finding out she was pregnant.

“I was a lot more aggressive and I just played like I had nothing to lose because I really didn’t, I felt like ‘Wow, no matter what happens I’m going to be winning, I’m having a kid’.”

Serena gave birth to one-year-old Alexis Olympia Ohanian Jr. last September and the sounds of her babbling can be heard clearly in the background of Serena’s interview on No Filter. It’s apparent that she’s close by, playing with mum, while she works.

Serena has regularly used the time since she’s become a mum to speak openly about its challenges and her personal struggles with being a working parent.

The tennis champion has used her experiences to encourage other mums to do the same. Most recently, she shared a story of Olympia vomiting on a plane to start a discussion about the realities of being a mum.

Mia Freedman asked about the way she’s made lifting women up her “mission,” even during a particularly low point at the US Open. Her public support of Naomi Osaka, certainly, was no accident.

“For me I feel like we should lift each other up and support each other, and not tear each other down, and that’s something I’ve always tried to do,” Williams said. “I’ve always tried to… fight for equal prize money and fight for equal playing time, and fight for all sorts of equality, and you know I feel like it’s one thing to fight for it and then not do it.”

It’s a value, however, that is entirely authentic to Williams. “It’s just me,” she said. “It’s just super, super, super, super natural.”

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