The sluggers also collected three RBIs apiece in the lopsided victory Tuesday at Busch Stadium in St. Louis. Cardinals ace Jack Flaherty allowed three hits and one run in five innings to move to 2-0 this season.
"That's exactly what we're expecting out of [the offense]," Cardinals manager Mike Shildt told reporters. "That's a very broad way of being able to compete regardless of situation."
Flaherty did not allow a hit in the first inning. Tommy Edman then started the bottom of the frame with a fly out, which prompted Goldschmidt's first walk to the batter's box.
The Cardinals first baseman sent the first pitch of his exchange with Nationals starter Stephen Strasburg into the left field seats. The 385-foot solo shot had an exit velocity of 106 mph, according to Statcast.
Nationals outfielder Juan Soto tied the score with an RBI double in the top of the third inning, but the Cardinals answered with four runs in the bottom half of the frame and never looked back.
Strasburg gave up a leadoff single to Tommy Edman to start the half-inning. He then forced Goldschmidt to pop out to third base.
Arenado stepped into the box as the third hitter of the half-inning. He proceeded to drive a 3-1 Strasburg changeup to left field for a two-run homer. That blast traveled 373-feet and squeezed just inside the left field foul pole.
Paul DeJong took a walk in the next at-bat. Carpenter followed with a two-run homer to right field. DeJong's 388-foot bomb had an exit velocity of 107 mph and gave the Cardinals a 5-1 edge.
The Cardinals added nine more runs with an explosive fifth inning.
Justin Williams, Goldschmidt, Arenado and DeJong each had RBI singles in the frame. Austin Dean and Carpenter also drove in runs with RBI sacrifice flies.
Nationals second baseman Josh Harrison drove in the final runs of the game with a two-run double in the top of the ninth inning.
Strasburg allowed eight hits and eight runs in four innings in the loss. Goldschmidt and Williams each went 2 for 4 with three RBIs for the Cardinals. Arenado went 2 for 3 with three RBIs. Carpenter went 1 for 4 with three RBIs in the win.
Harrison went 3 for 4 with two RBIs for the Nationals.
The Cardinals (6-5) host the Nationals (2-6) at 1:15 p.m. EDT Wednesday at Busch Stadium. Nationals right-handed pitcher Joe Ross and is expected to face Cardinals right-handed pitcher Adam Wainwright in the series finale in St. Louis.