Roger Federer headlines Davis Cup action this weekend.

Roger Federer confirmed his participation in the Switzerland-USA Davis Cup first round tie in February.

Novak Djokovic retires in Davis Cup with a back injury.

“It’s always interesting with them around, I’ll tell you that,” McEnroe said, to laughter from the press corp. “Where they are, hilarity ensues most times, in a good way. I get a kick out of watching them practice. Even when they’re on the practice court, they start fighting with each other, I just think it’s hilarious. They always add a certain dynamic to the matches. On top of that, they’re the No. 1 team in the world. That’s always something that you want to have on your side.”