WASHINGTON -- The Nationals had spoiled chances to score all night and were hitless in their first eight at-bats with a runner in scoring position as their offense leaned heavily on the solo home run. But with two on and two outs in the 10th inning, Bryce Harper strolled to the plate and what remained of the crowd of 36,347 fans at Nationals Park rose to its feet.
Harper delivered again in the clutch, lining a walk-off single to the warning track in right field off Raisel Iglesias to give the Nationals a 6-5 victory over the Reds on Friday night.
• Cast your Esurance All-Star ballot for Harper and other #ASGWorthy players
"I thought I had some good at-bats earlier in the game, just missing pitches I could drive," Harper said. "But [I was] just trying to grind it out and grind it out in that at-bat. Got a pitch I could handle and have it win the game."
Trea Turner and Brian Goodwin got the rally started with back-to-back two-out singles to set the stage for Harper.
"That's what you want," Turner said. "That's what they talk about in basketball is, 'Can you hit the clutch shot?' Same thing for baseball. It's a little bit more difficult because if you have a good at-bat, you can still get out. Tons of things can happen. … It's nice to have [Harper] right in the middle of the lineup and producing for us."
The Nationals relied on four solo homers -- from Anthony Rendon, Daniel Murphy and two from Goodwin, in the first and seventh innings -- to provide most of their offense.
It was the 19th come-from-behind victory for Washington, which fell behind after the Reds scored four runs in the first inning off Stephen Strasburg, who gave up five runs in five innings.
That gave Reds rookie Luis Castillo a cushion for his Major League debut. Castillo came out pumping fastballs that hit triple digits on the radar gun. Then, against the National League's best offense, Castillo wiggled his way out of trouble all night as he surrendered five hits and an uncharacteristic five walks. Still, his debut was solid with five innings of two-run ball with five strikeouts.
"Everybody can see the stuff that he has and kind of dream on that," Reds catcher Devin Mesoraco said. "He struck a couple guys out on his slider, he struck a couple guys out on his changeup. He certainly has the stuff, no doubt about it."
MOMENTS THAT MATTERED
Jumping out early: Castillo's Major League debut surprisingly came at the plate, as the Reds sent nine hitters to bat against Strasburg during a five-hit, four-run first inning. Scooter Gennett got things started with a solo home run before Cincinnati took advantage of some miscues from the Nationals defense. Wilmer Difo, who was making his first career start in center field, misplayed a ball into a double that helped lead the Reds to a strong start.
"The lack of add-on runs today really hurt," Reds manager Bryan Price said. "That's one that was sitting there to win. We just weren't able to get it done."
Goodwin ties it: Goodwin has been on a tear since becoming a regular on the Nationals' 25-man roster in late May, and he continued that power surge against the Reds. He launched his second home run of the game, off of Wandy Peralta in the seventh inning, to tie the contest at 5. It gave Goodwin his first career multi-homer game. He's played in 54 Major League games, but all six of his career home runs have come this month.
The Nationals came within one in the sixth inning behind Murphy's home run and Stephen Drew's sacrifice fly that was a few feet away from climbing over the center-field wall. But Goodwin ensured the Reds wouldn't escape with a one-run victory.
• Nats' Difo debuts in CF
SOUND SMART WITH YOUR FRIENDS
The Reds have allowed a home run in 16 consecutive games, one game shy of the team record.
Reds:Homer Bailey will make his first Major League start this season when the Reds play the Nationals at Nationals Park on Saturday at 4:05 p.m. ET in the second game of the three-game set. Bailey, who holds a career 4.24 ERA, underwent elbow surgery in February and has a 1.08 ERA in three Minor League starts this month.
Nationals: Searching for some consistency in what has been the most difficult season of his young career, Joe Ross will take the mound against the Reds. In his last two starts, Ross has given up nine runs (seven earned) in 11 2/3 innings with six strikeouts and four walks.
Watch every out-of-market regular-season game live on MLB.TV.