WASHINGTON -- Nationals manager Dave Martinez wants his high-flying sensation Juan Soto to stop worrying about the umpire and just worry about hitting.

In Sunday’s first at-bat against Rockies pitcher Kyle Freeland, Soto took that advice to heart and crushed a line drive two-run homer that flew easily over the left-center-field fence to give the Nats a 2-1 advantage.

The Nats held off a late Rockies rally, 6-5, to post their first series win at home of the season.

Washington has tallied at least one run in the first inning in five consecutive games against Colorado, dating back to May 5 in Denver.

Soto’s ninth round-tripper of the season traveled 399 feet at an exit velocity of 103.4 mph, scoring Lane Thomas in front of him. It was his first homer since May 12 against the Mets.

"He seemed a lot more relaxed,” Martinez said of Soto’s home run at-bat. “He wasn't as jumpy at the plate. Foot was down. I really felt like he's starting to swing the bat better. Today was a result of him getting up there and getting a good pitch to hit, swinging at it. He did well today. Hopefully this will kick-start him to continue to do what he does."

Soto walked for a season-high sixth straight game to lead off the bottom of the 5th inning. He also drove a double to right field in the sixth. But this day was all about the power display for Soto -- his 107th career HR.

"It feels pretty good,” Soto said. “I have been swinging the bat pretty well the last couple of days. I have been doing my homework, working on my swing, working on my stance and everything. Just feel great."

When Freeland fell behind 2-0, Soto expected the next pitch to be in the strike zone, so he zeroed in.

"I was looking for a fastball,” Soto said. “Just try to react. Slider was in the back of my head. He was telling the infielders to move over so that was telling me he was going to try to throw an off speed so I wasn't looking for it, but at the end of the day, it was right there in the back of my head."

"I think [Soto's] swing has been a lot better,” said Martinez during Sunday’s pregame. “One thing that I have noticed is I don't want him to become an umpire. I want him to just become a hitter. I think he is following the pattern where now he's trying to become an umpire and questioning a lot of different calls. That's not who he is.

"He's a guy who sees the ball and hits them. I've seen him hit balls out that were two, three, four balls off and hit them hard. I want him to be ready to hit every pitch.”

Soto was hitting .217 in May coming into Sunday’s finale versus the Rockies. He had struck out five times in the past five games, including three of his last four at-bats.

Martinez said Soto went through a bit of a slow start by his standards this time last season as well. He wants his best player to just go up there and hit the ball as hard as he can.

"He's our best hitter,” Martinez said. “We need him to hit. I need him to drive in runs. This team needs him to drive in runs. It's going to come. And when it does come it’s going to come in bunches. When he starts hitting the ball out of the ballpark it’s going to come in bunches.

"I look back at this time last year and he was hitting .240, .250, and then all of a sudden he took off. I am thinking about having a Home Run Derby one day [during] batting practice for him. Let him play Home Run Derby. See if that helps."

Soto said he knows his swing is getting back to where he wants it when he is able to drive the ball to the opposite field again.

"Exactly. Every time I hit the ball that way,” Soto said of the home run to left-center. “Yesterday I hit to center field. I know it was caught, but when I hit a ball like that, it is just telling you my swing is getting better and better."

Thomas broke out of an 0-for-18 slump with a two-run shot in the sixth. Nelson Cruz’s third double in the last two days extended his hitting streak to 10 games. Victor Robles had two singles, two stolen bases and a run scored.

Right-hander Josiah Gray (5-4) allowed one run on three hits over five innings for his fifth win of the season. Tanner Rainey came on for the final five outs to record his fifth save.