SAN FRANCISCO -- Receiving impressive pitching from Chris Heston and brief but effective flurries of offense, the San Francisco Giants snapped their eight-game losing streak Saturday by subduing the Arizona Diamondbacks, 4-1. The first defending World Series champions to drop their first five home games, the Giants finally emerged victorious at AT&T Park with sufficient backing for Heston, who yielded five hits in 7 2/3 innings. Joe Panik lined a first-inning RBI single, Buster Posey contributed a two-out, run-scoring single in the third inning and Brandon Crawford added a two-run homer in the fourth.