LISBON — Former Real Madrid goalkeeper Iker Casillas kept a clean sheet in his Portuguese league debut Saturday, when FC Porto beat Guimaraes 3-0 to start its season. Cameroon striker Vincent Aboubakar struck his first of two goals from Alex Sandro's deflected pass in the eighth minute. Maxi Pereira set him up in the 61st for a second goal. Silvestre Varela netted in the 84th to secure the first three points of the campaign for Julen Lopetegui's side. Elsewhere, defender Goncalo Brandao scored for both his Belenenses side and netted an own goal in a 3-3 draw with Rio Ave. — AP