A good tennis volley has a rhythm. As the yellow felt bounces back and forth over the net, a beat forms. In the crowd, heads oscillate with each swing. There's grunting and sweat, drama and action, until the ball breaks free from the tension, releasing an eruption of cheers and howls under the bright sun. That infectious passion of competition is on intense display in Luca Guadagnino 's new film, Challengers, about a tennis rivalry spiked with a love triangle.