PHILADELPHIA -- For anyone who may have been worried that the All-Star break might slow down the surging Nationals, the club quickly put those concerns to rest with a 4-0 win over the Phillies in Friday’s second-half opener at Citizens Bank Park.

Stephen Strasburg returned to the site of his worst outing of the season, but things went a bit different this time around. After all, this isn't the same Strasburg, these are far from the same Nationals -- and these certainly aren't the same Phillies.

The right-hander tossed six scoreless innings to help move the Nationals (48-42) ahead of the rival Phillies (47-44) in the win column for the first time this season. Washington improved to 16-4 in its last 20 games, a stretch that includes four wins in as many tries against the Phillies.

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"I’m really proud of the way the guys came out and played the game today," manager Dave Martinez said. "They had intensity. We continue to just keep playing baseball. I preach this all the time with them. I say, 'Hey, take care of the here and now, and let’s worry about today and let’s go from there.'"

Strasburg once again didn't have his best stuff against the Phillies, but he managed to work around seven hits and a walk over six frames, while striking out six batters. It was a far cry from his April 9 outing in Philadelphia, in which he was tagged for six earned runs in just four innings (his shortest start of the year).

"They're the kind of team that really battles you," said Strasburg, who had not pitched since July 3, when he struck out 14 over 7 1/3 scoreless innings against the Marlins. "Honestly, I thought my curveball wasn't very good tonight -- I threw it down, but I wasn't trying to. But [eight] days off, I can't be too picky about it. I know I'm really good when I have a routine, but unfortunately, it's something everybody has to go through. So I tried to go out there and battle tonight."

While the Nationals just keep winning, the Phillies fell to 8-13 in their last 21 contests. Put it all together, and the Nationals have a 1 1/2-game lead over their rivals for second place in the National League East and own the top NL Wild Card spot.

"It's huge," Strasburg said of picking up where they left off. "I just know in the past -- like when we've clinched early and kind of had that long layoff while all the Wild Card Games are going on -- we had a tendency to kind of come back out a little flat. But I think with us here, we've had guys that have been in that situation before, and I think we all knew what was coming.

"We weren't going to show up and just kind of be lackadaisical. We wanted to go out there and keep playing hard."

There was certainly no letdown this time around.

The Nationals jumped out to a 3-0 lead in the first three innings, and Strasburg combined with three relievers for the Nationals' seventh shutout of the season, matching their total from 2018. They received plenty of help from the defense, including a leaping grab at the wall by Juan Soto to rob Rhys Hoskins of extra bases to lead off the bottom of the fourth.

Soto said he was just trying to find a way to pitch in after striking out with runners at the corners and nobody out in the top of the third inning.

"It's really important," Soto said of winning the series opener. "The more a team is behind us, the more they want to beat us. But the first win is very important in every series."