HOUSTON, June 30 : Portugal and their talisman Cristiano Ronaldo will look to quiet critics of an underwhelming World Cup run in their round of 32 clash on Thursday in Toronto when they meet a Croatian side who have made a habit of outperforming on the biggest stage. The match potentially marks the end of an era with the 41-year-old Ronaldo and Croatia's 40-year-old midfielder Luka Modric looking to finally experience World Cup glory in the twilight of their trophied careers.  For Portugal, it