American tennis super star Serena Williams has sent a loving message to her unborn child as she maintains her No. 1 spot in the new WTA rankings.

Williams celebrated the news by posting a heart warming message on her Instagram profile.

“My Dearest Baby, You gave me the strength I didn’t know I had. You taught me the true meaning of serenity and peace. I can’t wait to meet you. I can’t wait for you to join the players box next year. But most importantly, I am so happy to share being number one in the world with you…. Once again today.On @alexisohanianbday. From the world’s oldest number one to the world’s youngest number one. –Your Mommy,” her message read.

She is expecting her first child with her fiancé Alexis Ohanian. Serena announced last week that she was 20 weeks gone and was expecting a baby with the Reddit co-founder. The post on Snapchat was later deleted but not before it went viral.

Williams played the Australian Open through her pregnancy. She said she discovered it two weeks before the tournament but still went ahead.

“I wasn’t sure what to do. Can I play? I know it’s very dangerous in the first 12 weeks or so, so I had a lot of questions,” she said. She added that her baby when born would be in the stands supporting her as she plays. She plans resuming next year but it would be quite a hurdle.