PHILADELPHIA -- The Phillies could not waste another Cy Young-worthy start from Zack Wheeler.

Not against the lowly Orioles.

Not if they want next week’s games in Atlanta to matter.

The Phillies kept their postseason hopes alive on Wednesday night with a 4-3 victory over the Orioles at Citizens Bank Park. They remained three games back of the Braves in the National League East -- thanks to Atlanta's win over the D-backs -- with 10 games to play. The Phils open a four-game series against the Pirates on Thursday night. It will not be easy to catch Atlanta at this point. If the Braves (80-70) finish just 5-7 for an 85-win season, the Phillies (78-74) would need to finish 7-3 to force a one-game tiebreaker.

• Box score

“Every game is a grind right now,” Phillies manager Joe Girardi said. “When you’re in it, it’s a good thing. We’re in it.”

The Phillies will need to play better than they played against the Orioles the rest of the way, even though they won the series. Baltimore is the worst team in the AL with baseball’s third-worst pitching staff in 82 years.

Yet Philadelphia scored just seven runs in the series.

“Maybe it’s not as easy as we wanted it to be, but, hey, it’s baseball,” Wheeler said. “We got the wins and that’s all that matters.”

The Phillies scored four runs late on Wednesday. Andrew McCutchen hit a two-run home run in the sixth inning to give the Phillies a short-lived one-run lead. Jean Segura’s sacrifice fly in the seventh regained it. After the Orioles intentionally walked Bryce Harper for a second consecutive night in a big spot to face J.T. Realmuto, Realmuto came through with another clutch hit to score an important insurance run.

The Phillies allowed a run in the eighth to cut their lead to one, but Harper’s remarkable flat-footed throw from right field nailed the potential game-tying run at the plate to end the inning.

Harper heard “MVP! MVP! MVP!” chants as he trotted off the field.

“He fielded it like an infielder almost,” Phillies first baseman Matt Vierling said. “He set his feet and just threw an absolute rocket to home plate. It was a huge play, a clutch play by him. He’s a clutch player.”

Wheeler allowed four hits, one run and two walks in six innings. He struck out nine. He leads baseball with 240 strikeouts, 206 1/3 innings pitched, three complete games, two shutouts and a 6.9 WAR, according to Baseball Reference. He is a frontrunner for the NL Cy Young Award, although Max Scherzer is building steam as the Dodgers try to catch the Giants in the NL West.

It is a crowded field that also includes Corbin Burnes, Walker Buehler, Kevin Gausman and Brandon Woodruff.

A strong case can be made for a few of them.

A strong case can be made for Wheeler, too.

Wheeler (14-9, 2.79 ERA) has been the Phillies’ ace all season, but lately they have been monitoring his innings as he enters uncharted territory, trying to limit his starts to 100 pitches to keep him as fresh as possible. (His four-seam fastball averaged 96.3 mph against the O's, almost 1 mph below his season average.) Wheeler reached the sixth inning at 97 pitches. Girardi said he never considered keeping him in the game, despite the bullpen being shorthanded.

“They’re just looking out for me,” Wheeler said. “I want to keep pitching for the rest of the season and hopefully into the playoffs. I think we’re helping that cause by doing what we’re doing.”

Wheeler’s next start is Tuesday against the Braves in Atlanta, where he grew up. It could be one of the biggest starts of his career.

“It’s another start for me,” Wheeler said. “I can’t get too worked up about it. I know it’s important. I know it’s a big series for us. But at the same time, I’ve just got to relax and pitch.”

But the Phillies will need to beat the Pirates to make Tuesday’s start matter. They hand the ball to Aaron Nola on Thursday night.