"He's thrown a lot of games," D-backs manager Kirk Gibson said of Arroyo. "So when you get in games like this and you're analyzing what you want to do, he's been through a lot of these battles and he's got a lot of different tricks up his sleeve. Early on, maybe he didn't have his best stuff, but then he got on a roll and had all his pitches working."
Arroyo, 37, changed speeds and arm angles with a fastball in the upper 80s and a breaking ball that was clocked as slow as 69.
"He knows how to pitch," Nationals outfielder Jayson Werth said. "He knows how to navigate a lineup. He throws from different arm angles. He mixes his pitches, moves the ball in and out. He had a really good sinker going. It's the best sinker I've seen. He is not a guy that is going overpower you. He is going to be smart, make you get yourself out, be crafty. He is a veteran guy that has been pitching a long time. He knows what he is doing."
In tossing the complete game, Arroyo (4-2) scattered seven hits and struck out seven while walking one.
"It's a lot of fun to watch," said D-backs pitcher Josh Collmenter, also someone without overpowering stuff. "You can't tell what angle he's going to throw it from, or how it's going to move -- is it going to sink? Is it going to slide? When he's healthy and he's right he pitches around the zone and just misses barrels so you see a lot of bad swings or guys not getting a whole lot of bat on the ball like tonight. It was fun to watch."
The Nationals touched Arroyo for a run in the second when Wilson Ramos led off with a single and scored when Ian Desmond followed with a triple.
Arroyo, though, pitched out of the inning without further damage, stranding Desmond at third.
"That was really big, especially not having any outs with a man on third and especially against a guy like Strasburg, you never know how [many runs] you're going to get," Arroyo said. "To get out of that is tough to do, but I got lucky with the strikeout and then kind of pitched around [Tyler] Moore to try and get the double-play ball."
The right-hander also pitched out of a second-and-third-with-one-out jam in the fifth.
Meanwhile Strasburg used a mid-90s fastball to try to overpower the Arizona hitters.
"Strasburg's got good stuff, boy," Gibson said. "He came out firing, seven pitches in the first inning and he was rolling. We put some good at-bats on him."
The D-backs finally got to the 25-year-old in the fourth when Paul Goldschmidt drove a 97-mph heater the opposite way down the right-field line for a double and scored when Miguel Montero hit a 94-mph fastball back up the middle for a single.
The D-backs tacked on a pair of runs in the fifth when Arroyo helped himself with a leadoff single and one out later, after Martin Prado singled, Goldschmidt doubled to left-center to give Arizona a 3-1 lead.
Arroyo became just the second pitcher to collect two hits in a game against Strasburg.
"It's not much of an approach up there," Arroyo said. "You freaking choke up a little bit and he's throwing hard. I just try to outthink him and try and guess what he's throwing. If you can guess what he's throwing, then you give yourself at least a chance. But I got lucky today. I hit two balls soft, but one of them turned out to be a huge hit and started off an inning that won us the ballgame."
With closer Addison Reed having pitched twice -- and warmed up once without being used -- in the past three games and setup man Brad Ziegler down after throwing three days in a row, it was left to Arroyo to finish it out.
The Nats looked like they might chase Arroyo from the game when they put a pair of men on base in the eighth, but he was able to get Werth to fly out to end the frame.
The complete game was the 16th of Arroyo's career and he is 3-0 with a 0.39 ERA in his last three starts.