Serena Williams is no stranger to the biggest stages ... As she reached the goal line, she celebrated with a triumphant pose, flashing a smile that reminded everyone why she's one of the most ...

Meghan Markle's daughter, Princess Lilibet, just had a play date with her superstar "auntie," Serena Williams.

Seated in the front row alongside Philadelphia Eagles teammates Avonte Maddox and Dallas Goedert, Williams raised ... although Serena continued to smile and laugh throughout.

Serena Williams once openly discussed the challenges of being a working mother as she juggled her tennis career with parenting her daughter Olympia.