WASHINGTON — The Cardinals’ offense, through the first 15 games this season, has been the epitome of touch-and-go. Entering Monday’s series opener against the Nationals, they had scored a respectable 71 runs, but nearly 50 percent of them came across a mere three games. Spin that another way — they’ve scored five or fewer runs 10 times.

Feast or famine? Not when Paul DeJong arrives at Nationals Park hungry.

DeJong unloaded a pair of blasts in the 12-5 drubbing of the Nats, including a grand slam in the fifth inning as part of a five-homer day for the Cards — their season high as a team. DeJong’s jacks came in tandem, thanks to back-to-back blasts by Tommy Edman and Paul Goldschmidt, as well as a laser off the bat of Justin Williams.

No player may be more indicative of the Cardinals’ offense as a whole than DeJong, who owns 10 hits through his first 53 at-bats. Half of them are homers.

And no one may be more appreciative of the offensive outbursts than Jack Flaherty, who tossed a quality start and has received 11 or more runs of support in three of his four starts this season. Under the necessity for deeper outings, Flaherty stayed past a visit from manager Mike Shildt for 107 pitches on the evening.

True is the fact that Flaherty was hit around in the sixth inning — when staked to a 11-2 lead, he conceded a trio of unearned runs. But also true is this — only one Cardinals starter has thrown a quality start (Flaherty, who’s done so twice), and only one has pitched into the sixth inning (Flaherty, also twice).