SAN FRANCISCO – It was a joyous celebration of the Giants' 2010 World Series title and an emotional triumph in a 12-inning marathon home opener, but Friday's festivities were not carefree.Paul Kitagaki Jr. pkitagaki@sacbee.comGiants pitcher Matt Cain, left, and third baseman Pablo Sandoval congratulate Aaron Rowand (33) after his single to the outfield wall drove home the winning run in the 12th inning against the St. Louis Cardinals at AT&T Park on Friday afternoon.