The U.S. Open marked a milestone Wednesday night when rain forced the new retractable roof over Arthur Ashe Stadium to close for the first time. ESPN, which broadcasts the two-week tournament, took full advantage of the six-and-a-half minutes it took for the roof to retract, airing reactions from players like Rafael Nadal right through the next morning's edition of SportsCenter. Behind the scenes, though, the network has been troubleshooting the production aspects of the roof and other enhancements to the fabled courts at the USTA's Billie Jean King National Tennis Center grounds in Flushing Meadows, Queens.