This has been quite an exciting, and exhausting, tournament so far – and yesterday’s games, particularly the tough loss by Andy Murray and, later, the intense win by Roger Federer that ended just before midnight, were long, grueling cappers to a wonderful tennis weekend at Flushing Meadows. And while today offers several matches, none is as anticipated as the quarterfinal match, at 7 p.m. ET, between Venus and Serena Williams (seen here at Wimbledon 2015). You know the stakes, and th