The event marked the duo’s first solo outing as sisters-in-law, People reported.
“We’ve always had a wonderful friendship,” Williams told Entertainment Tonight earlier this week. She added that Meghan had come to cheer her on at Wimbledon before.
Even though Meghan is royalty now, the pair’s friendship is “still exactly the same,” said Williams.
Despite Williams losing the match to Kerber, Meghan and Catherine appeared to have had some nice moments together watching the event: