Stephen Strasburg allowed two runs in six innings against the Phillies. (Matt Slocum/AP)

Stephen Strasburg’s first pitch during the Washington Nationals5-3 win at Citizens Bank Park on Monday night was a 92.8-mph four-seam fastball. It was called a ball, just inside on Roman Quinn, the Philadelphia Phillies’ speedy leadoff hitter. Strasburg’s second pitch was another four-seam fastball, slightly softer at 91.6 mph. Quinn connected and flied out to center field.

Two pitches, one out. A pitcher’s dream. Only this dream featured a chilling pattern lurking in the background. Strasburg’s first two four-seam fastballs shouldn’t have registered below 93 mph. He has been one of baseball’s best starters partly because of his ability to blow batters away. He is a power pitcher with a fastball that has regularly touched 97 mph in the early stages this season, even at age 30, and has never been forced to work with a fastball in the low 90s.

But that power was absent in his first start off the disabled list against the Phillies (70-61) last Wednesday, when he allowed five runs in four innings and didn’t resemble the $175 million pitcher the Nationals expect him to be. He and Manager Dave Martinez maintained he was healthy, that the cervical nerve impingement in his neck wasn’t a concern and the drop-off was stamina-related. But it remained alarming.

Strasburg didn’t return to his pre-injury form Monday, but, unlike in his previous performance, he effectively worked around his limitations. He posted just five strikeouts, including three in the fifth inning, but mixed and matched his way to six innings of two-run ball. He allowed five hits, walked three and threw 99 pitches.

“It was more consistent than the last start,” Strasburg said. “That’s a positive.”

Ryan Madson surrendered a solo home run to Rhys Hoskins in the eighth on his first pitch off the disabled list, but Justin Miller logged a perfect ninth to earn his first save in three years as the Nationals (66-66) began a three-game series against one of the two teams above them in the National League East standings with their second straight win.

Strasburg’s velocity crept up to 94 mph by the second inning and touched 95 on consecutive pitches to strike out Asdrubal Cabrera to end the third. That was as hard as his fastball went five days after it had precipitously dropped to 91 mph. Instead, Strasburg (7-7), whose fastball averaged 95.2 mph over his first 15 starts this season, relied on his off-speed stuff — particularly his devastating change-up — to successfully navigate through the Phillies’ lineup.

“The rust was off a little bit,” Nationals catcher Matt Wieters said. “He was able to make the corrections a little easier than his last start, which is big. Any time you’re coming back, being able to make the adjustment on the fly is big, and he was able to do that tonight.”

Philadelphia didn’t inflict damage on Strasburg until the third, which Strasburg began by yielding an eight-pitch leadoff walk to Nick Williams. Two batters later, after Phillies starter Zach Eflin moved Williams over with a sacrifice bunt, Quinn clobbered an RBI triple off the right field wall. Cesar Hernandez smacked an RBI single.

Hernandez’s hit tied the score at 2. The Nationals had gotten on the board first thanks to Juan Soto’s two-out RBI single in the first and Wieters’s first-pitch leadoff homer in the second. Washington added more in the fourth after Soto singled again to start the inning. He scored when Eflin (9-5) fielded Strasburg’s safety squeeze bunt with the bases loaded and saw his flip throw sail over the catcher’s head. A couple of batters later, Trea Turner hit a flare to left field that Hoskins should have caught, but the lumbering outfielder got a poor jump and the ball landed in front of him. Wilmer Difo scored on the miscue, and Washington had a two-run lead.

After the Nationals tacked on another run with Adam Eaton’s RBI double in the sixth, Strasburg took the mound for the bottom of the inning with his pitch count at 88. Already four pitches over his total from his previous start, he was being pushed to his brink and was teetering. First, Wilson Ramos stroked a single. Cabrera followed with a line drive to right field for another single. The Phillies were poised for a big inning. But Ramos, a slow-moving catcher further slowed by recent hamstring trouble, tried advancing from first to third at a speed approximating an unhurried jog and was thrown out on a one-hop strike from Eaton.

The play flipped the inning’s momentum, and perhaps the tenor of Strasburg’s outing. The Phillies went from possibly having runners on the corners with no outs to a runner on first with one down, and Strasburg capitalized. After getting Carlos Santana to pop out on a 3-2 curveball, Strasburg received a visit from Martinez. The manager asked him whether he had enough for one more batter. Strasburg was at 98 pitches. Martinez wanted to keep him around 100. Strasburg insisted he did and wanted to stay in the game. Martinez obliged.

Strasburg then spun an 85-mph slider to Maikel Franco to begin their battle. Franco pounced and grounded out. It was the final pitch Strasburg threw. He jogged off the mound satisfied. It wasn’t a classic Strasburg performance, but he didn’t need one for his first win in three months.

“I thought he was great,” Martinez said. “I mean, he didn’t have his 96, 97, but he pitched, and that was really encouraging to see.”