With a 1-0 lead, Matz walked the first two batters he faced in the third -- his first walks of the day -- before left fielder Alejandro De Aza lost a fly ball in the sun off Scott Sizemore's bat to give Brian Goodwin a chance with the bases loaded.
"You never care for walks," Matz said. "I just got a little erratic there. It's still early -- got something to work off there."
Terry Collins called on Bastardo, who gave up a one-run single into right field to Goodwin.
Bastardo proceeded to induce a shallow fly to center and then struck out Logan Schafer. Just when it seemed as if Bastardo would limit the damage to a 1-1 tie score after three innings, pinch-hitter Chris Heisey plated two with a single through the box into center.
"He's a big believer in command of the fastball," Collins said of Bastardo, who is also working on his slider. "That's the pitch he's throwing right now to try to get his command of it on both sides of the plate."
Tyler Moore flew out to center to end the third.
Matz had gotten a pair of groundouts and struck out Bryce Harper looking in the first, when he kept with his plan of inducing ground-ball contact.
"You never want to keep the ball in the air," Matz said.
Daniel Murphy singled to lead off the bottom of the second before Matz's throw to second on Clint Robinson's grounder went awry. With one out and runners at first and second, Moore popped to short, and then Wilson Ramos grounded into a forceout, keeping the Nats scoreless.
Matz said he had felt fine despite just three days' rest, and he was trying to focus on improving his work from the stretch.
"I think that kind of got away from me today -- eight straight balls there," Matz said. "Walks will kill you every time."
Zak Kerr is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.