Olympic gold-medal winner Andy Murray eked out a victory Saturday against Spain’s Feliciano López, advancing to the next round. In a match that lasted nearly four hours, Murray won the first two sets but slipped in the third before eventually capturing the fourth. “I was struggling a bit physically, and that made it challenging,” Murray admitted after the match. Meanwhile, No. 1 seed Roger Federer cruised to victory against Spain’s Fernando Verdasco in three sets. And on the women’s side, Serena Williams won two straight sets against Russian Ekaterina Makarova, who bested Williams in the Australian Open in January.