Edwin Jackson of the Washington Nationals pitches in the first inning against the San Francisco Giants at Nationals Park on August 12, 2017 in Washington, DC. (Photo by Greg Fiume/Getty Images)

Washington Nationals right-hander Edwin Jackson had another solid outing Saturday night, tossing five scoreless innings against the San Francisco Giants after a one-run first — all after waiting out a three-hour rain delay at Nationals Park.

Jackson (3-2) kept his composure after allowing a solo home run from Giants second baseman Joe Panik in the first inning, and was the winning pitcher in the 3-1 Nats victory. The 33-year-old’s ERA improved to 3.30 in five starts since joining the team. He struggled a little early, throwing 23 pitches (only 12 strikes) in the first inning. He threw 100 pitches and 58 strikes total.

“Jackson was a little shaky early, had a lot of pitches, but settled down in the middle innings and took us to our pen and took us to the seventh,” Manager Dusty Baker said. “The seven, eight, nine guys did their job again . . . I’m just glad he (Jackson) gave us a victory tonight and we had just enough offense.”

Jackson was originally scheduled to pitch Friday, but the game got postponed. The 15-year veteran had to mentally prepare to pitch again Saturday, and had to wait out an additional three hours because of more rain.

“It’s a little tough but that’s what we have to do as a professional,” Jackson said. “We have to make those adjustments and nobody wants to hear excuses. It’s tough for both teams and both teams played a good game. It was a good game out there.”

Jackson, was able to stay composed despite an apparent knee injury to Bryce Harper in the bottom of the first inning, which initially sucked the life out of Nationals Park as Harper was assisted off the field.

“Today was definitely one of those, dig-deep-and-see-what-you-made-of days,” Jackson said. “I was fortunate enough to come out with good results and also help out the bullpen at the same time with a solid six innings. It’s one of those days when you really don’t have your best stuff.”

Saturday’s performance was an extension from the Jackson’s last outing, Aug. 5 at Wrigley Field against the Chicago Cubs, when he threw four scoreless innings after allowing four runs in the first inning of the National’s 7-4 loss. He retired 10 straight hitters after he gave up a two-run home run to Alex Avila that put the Cubs up 4-1 in the first inning. He also struck out eight without issuing a walk.

Jackson, who signed with Washington on June 16, wasn’t originally moved into the team’s rotation because of injuries to others.

With Joe Ross announced out for the year after Tommy John surgery in July, the Nationals needed a fifth starting pitcher. Jackson, who spent a month prior with Class AAA Syracuse, got his first shot at the starting role when he started in Los Angeles against the Angels and got the win after allowing only three hits and two runs in seven innings.

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