PHOENIX -- With all the talk of Stephen Strasburg's innings limit, there was a moment on Friday night when it was worth wondering whether the Nationals would let him run up his pitch count trying to complete a no-hitter.He wouldn't have gone too far, manager Davey Johnson said. Johnson would have given Strasburg the hook around 115 or 120 pitches, even if he hadn't given up his first and only hit with two outs in the fourth inning. Instead, Strasburg pitched six innings and led the Nationals to a 9-1 win over the D-backs at Chase Field, their seventh straight, ninth in 10 games. They became the first club in the Majors to win 70 games and maintained their 4 1/2-game lead in the National League East, as the Braves beat the Mets. What do those numbers mean to the Nationals, who have the inside track on a postseason berth with 49 games remaining? "I want to be a big part of this team, so it's huge. Job's not done," Strasburg said. "I don't think any of us are satisfied. I think we still have our best baseball ahead of us." "We just need to keep going. I think the minute we start thinking about that stuff is when we get in trouble," added Ryan Zimmerman. "For now, we're just going to keep going and keep winning and see what happens." Strasburg, who picked up his 13th win and lowered his ERA to 2.90, was pitching with a stiff back he aggravated covering first base in the second inning. He tied a season high with four walks, all with two outs, and struck out six while running his pitch count up to 104. He allowed his only hit and Arizona's lone run immediately after a nine-minute injury delay that saw home-plate umpire Dale Scott exit the game. "It really affected him, and it's my fault," Johnson said. "I feel bad because I should've known it was probably going to take 10 minutes, and I let him stand there and so did all my coaches, so I'm going to get on them, too, for not bringing him in. But it's my fault." After recording the first two outs in the fourth on six pitches, Strasburg walked Justin Upton. He got ahead of Miguel Montero with a 1-2 count, but Montero's foul tip hit Scott in the face mask, knocking him out of the game. Strasburg, who meandered around the mound and threw a few pitches to catcher Kurt Suzuki during the break, threw two straight balls when play resumed, and Montero fouled off three pitches before taking ball four. Chris Johnson continued the two-out rally with an RBI single to left field that tied the game, 1-1. "It got a little stiff, especially standing out there for a little bit," said Strasburg, who struggled as a result when he tried too hard to locate his pitches. "It happens. I wanted to go out there and grind through it. ... I just needed to let it rip, and that's when I started getting my command back." "He's got good stuff, obviously. I thought we had a pretty good approach," said D-backs manager Kirk Gibson. "It's good stuff. You have to play a lot better to beat that. He's a tall order, and it wasn't in the cards for us tonight." Washington's lineup, meanwhile, pounded Arizona starter Trevor Cahill and three relievers for 11 hits. Steve Lombardozzi led the way, tying a career high with four hits and setting a new career best with four runs. Bryce Harper drove in two runs on two sacrifice flies. Zimmerman plated two more by crushing his 16th home run of the season in the fifth inning. Jayson Werth went 3-for-5 with two doubles and two RBIs. Adam LaRoche drove in his 74th run of the year. Michael Morse continued his recent tear, mashing another mammoth opposite-field homer over the 25-foot fence in right-center field. "It feels awesome. I'm just trying to get a good pitch to hit, see a ball up and take a good whack at it. There's not much to it," Morse said. "It's great. When you're getting production from one through nine in the lineup, it's a good team. You never know who's going to win the game for us that day." But the Nats have won 70 of them, despite their injuries and inexperience. It would take either a serious collapse or a startling run from another contender to keep them out of the playoffs. But that hasn't entered the mind of anyone in that clubhouse, or at least they wouldn't admit it if it has. "I don't think it's surprising at all. We're taking the field every night feeling like we're going to win this game," Lombardozzi said. "It's definitely a good feeling. It's definitely been fun." "I think we've got our blinders on right now, just playing," added Morse. "We don't know what tomorrow is going to bring. This is uncharted waters for a lot of guys in here. We like what we're doing. We want to keep doing what we're doing. We're to a point where we're not going to change a thing. We're just going to keep pushing. I think we like winning."