SCOTTSDALE, Ariz. (AP) Chris Heston stepped in when Madison Bumgarner was scratched and pitched four scoreless innings to help the San Francisco Giants beat the San Diego Padres 8-1 on Sunday.

Bumgarner has tightness in his rib cage and a nerve condition in his left foot. The ace left-hander said both issues were minor but he wanted to take care of them now rather than let them linger.

Heston allowed one hit, struck out four and walked none.

More from FoxSports

Denard Span hit a two-run double for San Francisco, and Brandon Belt added an RBI double. Prospect Mac Williamson hit his fourth home run, a solo shot, and a two-run double.

Padres starter Brandon Maurer completed three innings. The only hit he gave up was Williamson's shot. He walked one and struck out one.

Brett Wallace, Yangervis Solarte and Jose Pirela had the only hits for the Padres.