Nationals shortstop Alex Cora avoids incoming Pittsburgh runner Neil Walker while throwing to first in an attempt to turn a double play. (Jared Wickerham/Getty Images)

This spring, Michael Morse earned the Washington Nationals’ starting left field position, an elusive opportunity he had longed for his entire career, the chance he had spent a decade chasing as he hopped around three organizations.

Then the season began. Thirty at-bats into his first year as a major league regular, stuck on four hits, Morse had only made an argument for why it took so long.

Even then, Morse changed nothing. He had believed for years he deserved to be an everyday player, and two weeks wouldn’t change that. “That’s one thing that I won’t lose,” Morse said. “Confidence for myself.”

Since his rough start, Morse has replicated one of the hot streaks that catapulted him into the starting lineup in the first place, culminating with a performance Sunday that lifted the Nationals to a 6-3 victory over the Pittsburgh Pirates before 9,520 at PNC Park. Morse went 3 for 4 with his first home run of the season, a three-run blast in the third inning that helped give Jason Marquis his second win and sent the Nationals back to .500 on the season.

The Nationals provided at least a momentary break from their offensive stagnancy, piling up a season-high 15 hits and scoring more runs than they had in their three previous games combined. None of those hits came from Jayson Werth, who went 0 for 5 with a strikeout just as it seemed, following a deep home run Saturday, he might be breaking out. Werth did, however, assist on the game’s final out by throwing out Andrew McCutchen, whose questionable decision to tag up allowed Werth to show off his powerful right arm.

Still at least a week away from the return of Ryan Zimmerman, the Nationals, if they want to keep holding down the fort, need many members of its slumping lineup to snap out of funks. Morse, it seems, might be in the middle of doing that. After Sunday’s three-hit performance, Morse is 10 for his last 24 and has raised his average to .259 on the season — which, believe it or not, would be second-highest among Nationals regulars.

“It would be huge,” Adam LaRoche said. “You look at the averages right now, and it’s not real good. We don’t have a ton of guys on base. I don’t think you’re ever going to have everybody clicking at once, but we could have the majority of guys get going.”

Before Sunday, really, Morse had shown none of the power that, in the spring, gave the Nationals no choice but to hand him the open left field position. Morse drilled nine homers in Florida. If they gave out a Grapefruit League MVP trophy, the 2011 model would be resting on Morse’s mantle.

In the third inning Sunday, in his 59th at-bat of the year, Morse walked to the plate without a homer in the regular season. The Nationals had loaded the bases with no outs before Werth grounded into a fielder’s choice that eliminated the lead runner at home. The previous inning, the Nationals had stranded runners on second and third, and now they were in danger of wasting another rally.

Pirates starter Kevin Correia threw Morse an Easter present, a 2-1 fastball down the pipe. Morse didn’t miss it — he rocketed his first home run deep into the left field bleachers, putting the Nationals ahead, 4-1.

Morse had neither made any significant adjustments nor allowed himself to worry about the slow start. “My name’s in the lineup, I just go out there and play,” he said. But lately, he said, he has been starting his swing a split-second earlier, giving his swing better timing.

Marquis was not at his best, but he had all the runs he needed. Pitching on six days’ rest because of recent rainouts, Marquis’s sinker dove less and he left more pitches up in the strike zone than he had all season. The Pirates ripped eight hits and drew two walks, the same number of free passes he had issued in his first three starts combined.

Still, Marquis lasted six innings and relied on the same formula that gave him a rotation-best 3.26 ERA entering the game: He threw strikes and kept the ball on the ground. He threw 63 of 100 pitches for strikes, and 15 of the 18 outs he recorded were either strikeouts (three) or groundouts (12).

“I felt like I was getting better as the game went on,” Marquis said. “I felt like my stuff was getting better. I felt like I was stronger.”

And so, when Riggleman visited him with two outs in the sixth inning and asked if he could pitch to one more batter, Marquis told him yes. “He wanted no part of coming out of that game,” Riggleman said. McCutchen grounded to short, ending the inning.

Marquis also laced two singles to center. They will take offense anyway they can get it, but the Nationals would prefer that their best hitters be the ones who reverse the trend. At least one of them, it seems, is finally on his way. Said Morse: “I’m just going to keep doing what I’m doing.”