Each of the top four hitters in the Nationals' lineup - Cesar Hernandez, Juan Soto, Cruz and Bell - had two hits while combining to go 8 for 17.
Washington manager Dave Martinez feels Hernandez sets the tone of as the leadoff hitter. Hernandez was signed in the offseason.
''The key for him, don't try to do too much, just get on base,'' Martinez said. ''Right now, he's staying on the ball with two strikes, hitting the ball the other way and trying to get on base, which is awesome.''
Erik Fedde (1-0) allowed two runs and four hits in five innings, struck out six and walked two.
Three pitchers combined for four scoreless innings of one-hit relief.
''They were awesome,'' Martinez said of the trio of Sean Doolittle, Austin Voth and Paolo Espino. ''I've got all the faith in the world in those guys.''
Mitch Keller (0-2) struggled for a second straight start, giving up four runs, seven hits and three walks in 3 2/3 innings. His ERA is 9.39 after two starts.
''I'm cool with how I'm throwing right now,'' Keller said. ''I'm feeling really good. It was seven singles today. I just got to keep pushing forward.''
The Nationals had four straight singles to begin the game, including RBI hits by Cruz and Bell. Cruz singled in another run in the third to make it 3-0.
''When he gets hot, it's a sight to see,'' Martinez said of Cruz, signed as a free agent during the offseason. ''He's a professional hitter and has a lot of RBIs for a reason. Him and Josh Bell are swinging the bats really well right now.''
Hoy Park accounted for the Pirates' scoring with a two-run double in the second.
''We had Fedde on the ropes a few times and made him have to execute pitches and we just couldn't get the big hit,'' Pittsburgh manager Derek Shelton said.
The Nationals broke open the game in the middle innings, increasing their lead to 7-2. Cruz plated a run with a groundout in the fourth, Yadiel Hernandez doubled and scored on Lane Thomas' double in the fifth and Bell delivered a two-run single in the sixth with the bases loaded.
Bell has reached base in each of the Nationals' nine games. He played for the Pirates from 2016-20 and started in the 2019 All-Star Game.
''We are where we want to be,'' Cruz said of the offense. ''It's early in the season, but we're doing good things: getting on base, finding ways to score runs. That's what we need to be doing.''
TIME OFF FOR ROBLES
Nationals center fielder Victor Robles did not start for a second straight game. Instead, he did extensive pre-game work with hitting coach Darnell Coles.
Robles is hitless in 15 at-bats so far this season. He also batted .209 in 159 games the past two seasons.
The Nationals place infielder/outfielder Dee Strange-Gordon (illness) on the 10-day injured list and recalled outfielder Donovan Casey from Triple-A Rochester. Casey was one of four prospects acquired from the Los Angeles Dodgers last July in a trade for Max Scherzer and Trea Turner.
Washington also claimed outfielder Josh Palacios off waivers from Toronto and optioned him to Rochester. Palacios made his major league debut last season, playing in eight games for the Blue Jays.
Nationals: Martinez said Strange-Gordon was feeling better Friday, a day after being scratched from the lineup, but was unable to comment further.
Pirates: C Roberto Perez (bruised left quadriceps) left the game in the second inning after being struck by Cruz's foul tip . LHP Sam Howard (mid back muscle strain) began a rehab assignment at Low-A Bradenton. . OF Anthony Alford (right wrist strain) has started swinging a bat and could go on a rehab assignment next week.
Nationals: LHP Josh Rogers (1-0, 1.69 ERA) starts Saturday. He allowed two earned runs in 6 2/3 innings last season in his lone appearance against the Pirates.
Pirates: RHP Bryse Wilson (0-0, 6.75 ERA) will be making his second start of the season after giving up three runs in four innings Sunday at St. Louis.
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