As the saying goes, you’re entitled to your own opinion, but not your own facts. That applies to opinion writers, too. After the contentious US Open Women’s final between Serena Williams and Japan’s Naomi Osaka, virtually everyone weighed in — including people who know nothing about the rules of the game.

On this week’s edition of Beat the Press, Adam Reilly was joined by Dan Kennedy of Northeastern University, Callie Crossley of WGBH News, Lylah Alphonse of U.S. News and World Report, and Tom Fiedler of Boston University.