Yunel Escobar scores the go-ahead run in the 10th inning after a wild pitch by Phillies reliever Justin De Fratus. (Eric Hartline/Usa Today Sports)

The first week of the Washington Nationals’ season has been an adventure. But the concerns about the inconsistent bullpen and the meager lineup were covered up, at least momentarily, when novice first baseman Ryan Zimmerman made a diving play to his right with two Phillies on base and the Nationals clinging to a one-run lead in the 10th inning.

Zimmerman’s stop and flip to closer Drew Storen as he ran to cover first base preserved the Nationals’ tense 4-3 win Sunday over Philadelphia, avoiding a sweep at the hands of what could be one of the worst teams in baseball this season. The play prevented what could have been yet another blown lead by the bullpen — and the second in one day after left-hander Xavier Cedeno turned a one-run lead into a tie game in the seventh inning. It also held off further questions about an offense that has been paltry but managed to deliver in extra innings and could get help in the form of Jayson Werth on Monday.

“We’ve dealt with our fair share of adversity out of the gate here, so it’s a good one to kind of save a little bit here,” Storen said. “Something for us to build off of. Wasn’t the prettiest one, but we got it done.”

Through six games this season, albeit a small sample, the Nationals’ starting rotation has been as strong as expected. Max Scherzer fired six solid innings against the Phillies, allowing one run and striking out eight. The Nationals’ rotation has a 1.91 ERA through 372 /3 innings. But in four games, the Nationals have had a lead in the sixth inning or later and then lost it, including Sunday.

Scherzer wasn’t his sharpest to begin Sunday’s affair, but his stuff was good enough to neutralize the Phillies’ lineup. He used his array of pitches, including his new cutter. In a critical moment of the game, Scherzer’s intensity came through.

Drew Storen and Bryce Harper celebrates the Nationals having avoided a sweep as they head to Boston next. (Eric Hartline/Usa Today Sports)

With his team leading 2-0, he backed himself into a corner with mistakes in the fifth. The opposing pitcher, Sean O’Sullivan, put up a fight, and Scherzer walked him on eight pitches. Ben Revere slapped a single to right, and Cody Asche did the same to drive in a run.

With two outs and runners on second and third, Scherzer missed with his first pitch to Ryan Howard but came back with a vengeance. He fired a 1-0 change-up for a swinging strike. Then he reared back for a 95-mph fastball that Howard also missed. Scherzer again found another gear and fired a 97-mph fastball past Howard’s overmatched bat. Scherzer let out a scream, spun around and bounced off the mound.

“I can always reach back and get more,” he said. “I didn’t have good rhythm today out of the windup. That’s where I felt I was most inconsistent. But once I got out of the stretch, I felt I was able to dial it in and execute pitches the way I wanted to.”

Scherzer gave the Nationals one more inning, his day complete at 102 pitches. But the bullpen had to protect the 2-1 lead over the final nine outs.

Manager Matt Williams called on left-handed specialist Cedeno, who made the team on the final day before the season after an inconsistent spring. Due up to bat: a pinch hitter, who Williams knew was going to be right-handed; left-handed Revere; and switch-hitting Freddy Galvis. Phillies Manager Ryne Sandberg sent right-handed Darin Ruf up to bat.

“Then he gets to the top of the lineup, and we have three out of four lefties,” Williams said. “The way that things have gone so far this season, we don’t want to burn two for one there.”

Cedeno’s fourth pitch Sunday, a high fastball to Ruf, was clobbered into the left field seats to tie the game. Cedeno escaped the inning after allowing another single, and the rest of the Nationals’ bullpen did well until the 10th inning. Craig Stammen fired a scoreless eighth, another solid inning in his third straight day of work. Aaron Barrett added a 1-2-3 ninth inning to extend the game and set up the decisive 10th.

Nationals beat writer Chelsea Janes talks about the three areas of concern for the World Series favorites ahead of the team's season opener against the New York Mets on April 5. (Jayne W. Orenstein/The Washington Post)

A leadoff double into the right field corner by Yunel Escobar, whose consistent contact has been a welcome addition to a shorthanded lineup of all-or-nothing hitters, started the Nationals’ winning rally.

“I just wanted to get to first base,” Escobar said. “We needed to score a run because we were in extra innings.”

Williams called for Bryce Harper, who hit a solo homer in the first, to bunt against hard-throwing left-hander Jake Diekman. Harper couldn’t, but he managed to ground out to first base, moving Escobar to third.

Escobar scored when Phillies reliever Justin De Fratus’s wild pitch went to the backstop. Wilson Ramos, who also drove in a run with a sacrifice fly in the fourth, added a critical insurance run when his single drove in Clint Robinson, whose three-hit day was the first by a National this season.

Then came Storen’s turn, and he injected more drama into the game with a shaky 10th. Ahead by two runs, he walked the first two batters he faced and drew pitching coach Steve McCatty out of the dugout. Storen, in his first appearance since Wednesday, found himself speeding up too much. He slowed himself down.

Storen notched a strikeout and flyout, but he then gave up a run on an infield hit to third base by Odubel Herrera. Storen fired a first-pitch sinker to the next batter, Cesar Hernandez, who hit it into the ground toward the right side. Shielded by Herrera, Zimmerman managed to keep an eye on the ball, dive to his right and toss it to Storen, saving the game.

“That’s a really incredible play,” Storen said. “This early in the season, for him to be making the adjustment that he has, it’s pretty incredible and it’s fun to watch.”

“I’m getting a better feel and sense about where I am on the field,” Zimmerman added. “Just as good a play by Drew to make sure he gets over there. It’s a lot easier when the pitcher is where he’s supposed to be. And ready to catch the ball, it’s easier to make that throw.”

Waiting in the clubhouse after the victory was Werth, who will travel with the team to Boston and could be activated from the disabled list Monday after completing the rehab on his surgically repaired shoulder. He may help boost a Nationals offense that has scored only 13 runs in six games.

“We didn’t score a lot of runs, and we didn’t play like we should, and we still had a chance to win every single game,” Zimmerman said. “That shows you what we can do. I think we just take this game and hopefully roll with it.”