The Nationals didn’t get another hit until Trea Turner’s two-out single in the ninth inning, before Foltynewicz struck out Harper to end the game on his 107th pitch and 77th strike.
In one of the two best performances of Foltynewicz’s career, he limited the Nationals to two hits and one walk with 11 strikeouts, mixing 97-99 mph fastballs with curveballs and sliders to overpower plenty of hitters and leave others looking perplexed.
Strasburg also had a shutout going until the seventh inning, when the Braves scratched out a run on consecutive singles by Nick Markakis and Kurt Suzuki and an error by first baseman Matt Adams on a swinging-bunt of a grounder by Johan Camargo that let in a run. Markakis scored the 1,000th run of his career on the Adams error.
One out later, Swanson crushed a low, two-strike curveball, pulling it to the back wall of the left-field bullpen for his fourth homer and a 4-0 lead.
Strasburg, who was charged with seven hits, four runs (three earned) and no walks with 10 strikeouts, left the game with two outs in the seventh inning after experiencing cramping in his left (non-throwing) hand and forearm.
For Foltynewicz, it was the best game he pitched since taking a no-hitter to the ninth inning at Oakland on June 30, 2017, before giving up a leadoff homer to Matt Olson that ended his night after 119 pitches. He had four walks and eight strikeouts in that game.
On Friday, he didn’t walk a batter until Juan Soto to start the eighth inning. Soto was the first to reach base for the Nationals since Harper’s one-out single in the first inning.
Brian Goodwin followed Soto by grounding into a force at second and hustling to beat the relay to first and avoid the double play. But Foltynewicz promptly picked off Goodwin at first base and struck out Pedro Severino to end the inning, making it 24 outs in 25 batters faced through eight.
The Braves won the first two games of the four-game series to move from a half-game behind the Nationals in the National League East standings back into first place, 1½ games ahead of Washington.
Foltynewicz dominated a Nationals team that had 16 homers and an .844 OPS while winning eight of nine games to move into first place before coming to Atlanta.