Andy Murray wasn't the only one feeling pain Monday at the Australian Open. While Murray's anguish was mostly psychological - the fourth-seeded Scot was ousted by Spain's Fernando Verdasco 2-6, 6-1, 1-6, 6-3, 6-4 - three other players had to quit mid-match with injuries or illness, paving the way for Serena Williams, Gilles Simon and Svetlana Kuznetsova to reach the quarterfinals.