SEATTLE -- Of the 520 games Dominic Smith had logged across 24 Major League ballparks, his schedule had not taken him to Seattle. The first baseman has played in the National League his entire career and had faced only nine Interleague opponents on the road. 

Taking the field at T-Mobile Park on Monday night for the first time in his seven-year career, Smith had an introduction to the stadium with its ups and downs. 

“You try to get to the ballpark early, go out on the field and take it all in,” Smith said following the Nationals’ 8-4 loss to the Mariners. “I got here pretty early before BP, and I just was walking around, just trying to look at the batter’s eye … It’s a beautiful ballpark.”

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Stepping to the plate for the first time at the stadium, Smith belted a solo home run off right-hander Luis Castillo in the second inning. He sent the ball flying a Statcast-projected 374 feet to right field at an exit velocity of 104.2 mph. Having never played at T-Mobile Park, Smith became the first Nationals player to homer in his first plate appearance at a specific ballpark since Joey Meneses went yard last season on Aug. 8 at Wrigley Field.

“I was trying to stay within myself, but at the same time, just trying to hit the ball hard,” Smith said. “I know it’s in there, so I’ve just got to keep grinding, keep putting in the work early that I come in and put in. The results, they’ll come.” 

The dinger was Smith’s third of the year and second in June. He is coming off a series in San Diego where he made hard contact at Petco Park. Manager Dave Martinez has encouraged Smith to focus on keeping his legs underneath him and driving the ball to the middle of the field. By not trying to do too much, Smith was able to identify an opportunity against Castillo and came away with a 2-for-3 night.

“Castillo made a couple mistakes, I was able to hit some balls hard,” Smith said. “I look forward to capitalizing on a lot of mistakes. I think I’m simplifying it right now, especially my swing -- staying back on pitches a little bit more and taking my shots. I think it’s starting to show a little bit.”

The newness of the ballpark impacts the defensive end, too. In the fifth inning, Teoscar Hernández singled a ball off the bottom of reliever Cory Abbott’s cleat. The ball went airborne, then dropped in front of Smith as he ran in toward the mound. 

Thinking he had a play to nab Hernández, Smith backhanded the ball to first. But Hernández was the only player there, and he safely reached the empty base. 

“That play happened so fast,” said Smith. “[Second baseman] Luis García’s going up the middle to make the play, I’m running to the ball, I see a shadow out of the corner of my eye, I hear the first-base coach screaming, ‘Come! Come! Come!’ So I’m thinking that I’ve got a play at first. I saw the shadow, tossed it. It ended up being the umpire.”

The ball traveled into foul territory, and Hernández advanced to second on a throwing error by Smith. That play began a three-run fifth inning for the Mariners.

“This is creating something that’s not there, and that’s something that we’ve got to stay away from,” Martinez said. “The ball hit Cory -- pick it up, keep him at first base, let’s try to turn two.”

Smith is almost halfway through his first season with Washington, having signed a one-year deal in January. He joined the Nationals looking to bounce back from struggling in his final season with the Mets, and he is batting an improved .259 with 22 multihit games and a .992 fielding percentage as the starting first baseman. 

“It’s a lot of grinding,” Smith said of this season. “I think that there’s still room for improvement -- offensively, defensively -- and we’ve still got some season left. I feel like I can help this team in a lot of ways, and if I can just build on today, who knows what everything will look like at the end of the season.”