Bryce Harper and Ryan Zimmerman celebrate after scoring in the third inning. (Greg Fiume/Getty Images)

Another fine pitcher took the mound against the Washington Nationals’ resurgent offense Wednesday and met the same result: not just a loss but a whipping by a lineup that, earlier this season, might have succumbed to an early deficit.

On this day, without their best power hitter this season or their regular catcher, and facing one of the major leagues’ best left-handed starters, the Nationals dispatched the San Francisco Giants, 9-4. They did so with a four-home run day, contributions from two rejuvenated veterans in the middle of their order, their sparkplug backup catcher and an outfielder known mainly for his defense. Everyone, at least for now, can hit.

Third baseman Ryan Zimmerman and outfielder Michael Morse hit back-to-back home runs in the fifth inning, turning a one-run lead into a rout. Jhonatan Solano, the Nationals’ fifth catcher this season, had his best day at the plate, going 2 for 4 with an impressive opposite field home run. Rick Ankiel, used mainly in the late innings as a defensive center fielder, added a two-run blast late in the game, further tormenting the Giants’ pitching staff.

San Francisco entered Nationals Park on Tuesday with the second-best record in the National League and one of the best pitching staffs in the game. The Nationals’ newly potent offense hammered Tim Lincecum, a two-time Cy Young Award winner, in the series opener, then manhandled Madison Bumgarner, a 10-game winner with a sub-3.00 ERA. The Nationals matched their high-water mark for the season at 15 games over .500. They own the best record in the National League and a 4½ -game lead in their division.

“We really don’t know how good this team can be,” Morse said. “I think that’s what makes us so great. The sky’s the limit.”

In the past week and a half, the Nationals have shed their status as one of the lowest-scoring teams in baseball behind the emergence of Zimmerman and Morse. They have scored at least five runs in each of the past eight games. In the eight games before that, they scored five runs once. The best pitching staff in baseball has finally been buoyed by the team’s bats.

“We’re doing the things I know we’re capable of doing, which is fun to watch,” Manager Davey Johnson said.

Starter Edwin Jackson rebounded from his worst outing of the season and a tough first inning on Wednesday. He found his fastball velocity again, hitting 92 and 93 mph in the first inning, but struggled with his control. The Giants scored three runs in the first on a sacrifice fly and a two-run home run. Over the next 42 / 3 innings, however, Jackson regained his innings-eating form, allowing only one more run and allowing Washington’s offense to seize the game.

Earlier in the season, a 3-0 deficit would have been difficult for the Nationals to surmount. Zimmerman, who bats third in the lineup, was crippled at the plate by his sore right shoulder and Morse, who hit 31 home runs last season, was practically in spring training mode after missing the season’s first 50 games.

Responsibility for offensive production fell squarely on players such as Ian Desmond, Adam LaRoche and some of the team’s rookies. Desmond rose to the occasion, blossoming into a potent hitter, notching a career high in home runs by June and earning his first all-star selection. LaRoche, a consistent force throughout his career, has emerged as the team’s best power hitter, driving in 50 runs before the midway point of the season.

Now that Zimmerman and Morse have finally come around, everyone’s load has been lightened. Johnson can afford to sit LaRoche against left-handers, as he did Wednesday, because of the production of rookie Tyler Moore, a right-hander. Solano can give regular catcher Jesus Flores a break without production dropping off. And rookie Bryce Harper can work out of a slump without hurting the offense.

Since June 25, Zimmerman is 15 for 43 with four home runs and 15 RBI, while Morse is 17 for 39 with three home runs and nine RBI. In the previous 66 games, the two had four home runs combined.

“I always put it back to the middle of the lineup,” Johnson said. “Those are the guys who are your best hitters, and when they struggle it has an effect on everybody else trying to do too much — trying to pick it up, trying to hit the ball out of the ballpark. But when they’re doing their thing, everybody else is just looking for a pitch to hit hard and, consequently, you get better pitches to hit and you’re a better hitter.”

In the third inning, Zimmerman drove in Danny Espinosa with a two-out double to left that missed being a home run by inches. It hit just below the red flowers that line the green padding along the left field wall. Morse then drew a walk and Desmond laced a two-run single up the middle to tie the game at 3.

An inning later, Bumgarner went after Solano, playing in his ninth game of the season, with sliders. After Solano fouled off four pitches, Bumgarner tossed him a backdoor slider and Solano drilled it to the right-center seats for a 4-3 lead.

An inning later, Zimmerman hit a laser two-run shot that sliced into the right-center field seats. Four pitches later, Morse added a third opposite field shot, a no-doubt solo home run into the right field bullpen. Solano chased Bumgarner from the game with his second hit in the sixth inning. And Ankiel, who came in to play center field in the eighth inning, crushed a two-run home run into the same busy right-center field seats. It was only the sixth time that the Nationals have hit four home runs in a home game since 2008.

“The biggest thing to describe the offense is just that it’s healthy and consistent, which is what we envisioned it would be from the beginning,” Zimmerman said. “We just had some speed bumps along the way.”