WASHINGTON -- The Nationals entered Spring Training with a renewed focus on fundamentals, vowing -- as so many teams often do -- to play better defense, run the bases more crisply and execute the so-called “little things” that make up the small differences in close games. The first two games

WASHINGTON -- The Nationals entered Spring Training with a renewed focus on fundamentals, vowing -- as so many teams often do -- to play better defense, run the bases more crisply and execute the so-called “little things” that make up the small differences in close games.

The first two games of the 2019 season, including Saturday afternoon’s 11-8 loss to the Mets, have offered a harsh referendum on those plans. Washington has dropped the opening two games of the year after being set back by defensive miscues, struggles on the basepaths and ineffective relief pitching late in games.

Both of their two biggest offseason additions in the bullpen -- Trevor Rosenthal and Kyle Barraclough -- scuffled in the eighth inning, turning what was a tie game into an 8-4 Mets lead. Rosenthal, pitching in his first regular-season game since August 2017 after missing last year’s action while recovering from Tommy John surgery, started the inning and did not retire a batter (three hits and a walk). Barraclough replaced Rosenthal with runners at the corners and no outs, but he balked home a run before his first pitch, then gave up a hit that led to another.

“We battled back,” manager Dave Martinez said, “and then the game got away from us in the eighth inning.”

Washington’s bullpen continued to struggle in the ninth inning, when New York tacked on three more runs off the combination of Wander Suero and Matt Grace . It put the game out of reach, even beyond a late charge from the Nats in the ninth, when they plated four runs, including three on a double from Ryan Zimmerman .

But the Nationals are counting on both Rosenthal and Barraclough to be important additions to their bullpen this season. They’re expected to be the top two set-up men ahead of closer Sean Doolittle .

“It was a good day, a good step forward getting back, but obviously didn't end up how I wanted it to,” Rosenthal said. “I felt good. Everything was good. Just make a few adjustments, and I can get back out there.”

Another player the Nationals are hoping can make adjustments is outfielder Victor Robles , the team’s top prospect and MLB Pipeline’s No. 4 overall prospect, who began the year as the starting center fielder in the big leagues for the first time. After making a key baserunning mistake in Thursday’s season opener, Robles had a few more miscues on the field Saturday. He could not come down with a leaping catch in center field in the first inning that led to a Jeff McNeil triple, then got a poor jump on a double from Pete Alonso in the second. It forced Stephen Strasburg to make some extra pitches before he settled down to complete six innings of four-run ball with eight strikeouts.

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Robles began making up for those defensive mistakes at the plate, swatting a home run to begin the third inning, then starting the fifth inning with a single. But he was promptly picked off at first base on a close play that the Nationals decided not to challenge. The Nats have high expectations for their talented 21-year-old outfielder, but they may have to live with some growing pains in the minor parts of his game.

“He's going to get better,” Martinez said. “You've got to remember he's 21 years old and he's playing in the big leagues. I've been there. I know the struggle. He's going to get better.

“He’s just a young kid just trying right now to piece it all together. And it’s going to come. I watch him. He wants to do a little more right now. It’s two games. … But what I see is someone who’s going to help us win a lot of games.”

Robles has been far from the only Nationals player who has not played fundamentally sound baseball to start the season, but these mistakes have been magnified throughout the opening games of the year. Two games is way too early to panic, but it’s not the start the Nats envisioned after spending the spring working to clean up those fundamental mistakes.

“We’re looking at maybe one or two things that happened,” Martinez said. “I’m also seeing some good things. … It’s two games. We would have liked to have won both. We have tomorrow.”

Jamal Collier has covered the Nationals for MLB.com since 2016. Follow him on Twitter at @jamalcollier.