DETROIT -- Mitchell Parker was one out away from completing the Nationals’ fifth scoreless inning of the night at Comerica Park against the Tigers.

A 34.5 mph dribbler toward the mound by Andy Ibáñez seemed like a routine play that would send the Nats back to the dugout. Instead, the ball bounced off the rookie southpaw’s glove, then the Tigers cleared the bases two batters later on a Little League home run by Riley Greene.

But after five more innings and four scoreless relief appearances, the Nats were able to look back on the misplay as a learning moment. Washington overcame a one-run deficit in the eighth to win the series opener, 5-4, in 10 innings.

“PFPs! We’re going to do PFPs!” manager Dave Martinez said with a grin. “I sat there scratching my head, like, you can’t get a ball easier than that. That’s why this is a funny game. Sometimes things happen, but I’m really proud of the boys for battling tonight.”

Parker pitched 4 2/3 innings in his first appearance against the Tigers. He allowed four unearned runs and three walks while striking out one batter across 81 pitches (46 strikes). Parker, who debuted on April 15, became the first Nationals pitcher since Joe Ross in 2015 to record an ERA of less than 3.25 in his first 11 career starts.

Parker had recorded one out when he walked Ryan Kreidler in the fifth inning. A popup by Matt Vierling put Parker one out away when Ibáñez's error occurred. Parker loaded the bases on a walk to Mark Canha, setting the stage for Greene’s bases-clearing triple to deep right field. The relay throw from second baseman Luis García Jr. to third base was errant, allowing Greene to score the fourth run.

“I let the game speed up on me,” said Parker. “I tried to make the throw before I even fielded it. I’ve got to be better than that. We do it a lot during Spring Training, do it a lot while we’re here. Just can’t let that happen.”

That prompted a call to the bullpen for Derek Law, sparking the relievers to shut down the opposing offense as their own bats climbed back with sacrifice fly balls from Ildemaro Vargas in the eighth and Lane Thomas in the 10th. The ‘pen allowed only two hits and one walk with 10 strikeouts in 5 1/3 frames.

“Keep it going boys,” Parker said.

Law fanned four batters in 1 1/3 innings to establish the tone. Dylan Floro then efficiently retired the side in the seventh on only six pitches. Hunter Harvey gave the Nationals an extended 1 2/3-inning performance (he surpassed his 30-pitch-count goal by two), and closer Kyle Finnegan earned the win after pitching into the 10th inning.

“Great job,” Finnegan said. “[Law] has been a rock for us getting us through those middle innings. He does a lot of different things. He’s kind of like a Swiss Army Knife down there, so we’re lucky to have him. Floro does his thing -- it seems like he’s only out there for like 45 seconds every time he pitches, which is a good thing. We’re all trying to be like him for sure. Then Hunter comes in there and sets the tone, punching guys out, throwing hard. I just tried to keep that momentum going.”

The Nationals extended their winning streak to four games and improved to 3-28 when trailing after the seventh.

“The character they showed tonight was awesome,” Martinez said. “We had the lead, we lost the lead. They fought, they scratched and clawed. The guys at the back end of the bullpen kept it together, and we were able to score one more than them. Sometimes, that’s what it takes.”