Eighteen years later at the Australian Open, when Caroline Wozniacki beat Simona Halep to win her first major, their prolonged embrace looked more like two camp friends saying goodbye at the end of the summer than two top-flight athletes after a fierce battle. Same when Sloane Stephens defeated her close friend Madison Keys to win the 2017 U.S. Open. As they waited for the trophy presentation, Stephens and Keys sat side by side, laughing.

So why has on-court hugging become a thing? Has everyone on tour suddenly become BFFs?

“You’re not going to do it with everyone,” said Kevin Anderson, the 2017 runner-up at the U.S. Open. “But most guys know that we’re out there working as hard as we can. We’re all competitors, but we’re also friends.”

For Djokovic, hugging has become part of his mental routine, the result of time with Pepe Imaz, a Spanish spiritual guru who specialized in a technique with meditation and prolonged hugs called Amor y Paz (“Love and Peace”).

Allen Fox, a California-based sports psychologist who has counseled athletes for more than 40 years, said hugs now are “part and parcel of every athletic competition, no matter the sport.”

“Back in the day, athletes were trying to be classy, so they kept their emotions in check, shook hands at the end of a match and left the court,” he said. “Men, in particular, were taught to be strong, not to share their personal struggles and to be quiet about their issues. They were trained not to be sappy out there , to take a loss with a stiff upper lip.

“Now people think nothing of hugging and crying after their matches.”

Even when post-match hugs aren’t warranted or wanted, most players now opt for a modified “bro-shake” — a bring-it-in handshake that turns into a one-armed hug. It is often accompanied by chest pats or back pats, especially among the men.