Patrick Bailey crushed a walk-off, three-run homer with no outs in the bottom of the ninth inning Friday night, producing the only scoring of the San Francisco Giants' 3-0 victory over the Pittsburgh Pirates.

After Camilo Doval (2-0) had pitched out of a bases-loaded jam in the top of the inning, Pirates closer David Bednar (1-2) walked Michael Conforto and served up a single to Matt Chapman to start off the bottom of the inning.

A wild pitch advanced the baserunners, but rather than intentionally walk Bailey to load the bases and create a potential forceout at the plate, Bednar grooved a 1-1 fastball that the San Francisco catcher drilled over the right field wall for his third homer of the season.

The Pirates threatened in the top of the ninth against Doval, loading the bases on singles by Oneil Cruz and Michael Taylor and a one-out walk by Andrew McCutchen. Doval turned a comebacker from Bryan Reynolds into a 1-2-3 double play to preserve the tie.

The Pirates were denied the game's first run earlier because of a rarely seen rule involving a hit batter.

Hitting with the bases loaded and a 2-2 count in the seventh, the Pirates' Reynolds was hit in the foot by a breaking pitch from Ryan Walker. However, because Reynolds swung and missed at the ball in the dirt, the ball was ruled dead upon making contact with the batter and an inning-ending strikeout was recorded as the ball rolled away and Taylor scampered home.

Walker had taken over for Giants starter Kyle Harrison, who shut out Pittsburgh on five hits over the first six innings. He struck out seven without issuing a walk.

Walker was matched pitch for pitch by the Pirates' Quinn Priester, who allowed just three singles in his six shutout innings. He walked one and fanned six.

Bailey's homer was the only extra-base hit for the Giants, who won for the third time in their past four games despite getting out-hit 8-6.

Ke'Bryan Hayes, who made a key defensive play in the eighth inning to prevent a Giants run, and Taylor had two hits each for the Pirates, who lost their third straight.

The contest was the opener of a three-game series.