Serena Williams and fiance Alexis Ohanian welcomed their baby girl into their lives on Friday.

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While Williams' daughter did not choose the timing of her emergence, her birth marks a key, and most likely unintentional, moment in Williams' rivalry with Russian player Maria Sharapova.

"Maria Sharapova is back," the tennis world exclaimed this week as she returned from a 15-month suspension.

But the headlines were quickly overshadowed by news of Williams’ delivery.

A short dive into history shows that this isn't the first time it's happened; Williams chose an interesting day to announce her pregnancy earlier this year -- Sharapova's birthday.

As it turns out, others have also noticed:

More on Williams-Sharapova's rivalry can be found here.