"That game was right up there with some of the really good ones he's thrown," Giants manager Bruce Bochy said.
The Giants' ace matched his career high with 14 strikeouts and slugged his fourth homer of the season with Marichal in attendance.
"It was fitting," Bochy said. "That's what Marichal did so many times."
On an 85-degree day, the hottest temperature recorded on a first pitch at AT&T Park since 2010, Bumgarner was even hotter.
The left-hander opened the game by striking out the side in order, fanning the Nationals' 1-2-3 hitters swinging.