Before the Washington Nationals hit the postseason, their schedule has asked them to confront an old bully. The Nationals play six of their final nine games against the Philadelphia Phillies, still the reigning division champion for eight more days, even if math ensures they will not win a sixth straight title.

Empty seats dot Citizens Bank Park these days. Players with unfamiliar names fill the Phillies’ pinstriped uniforms. The crown has fallen off their head and shattered into a thousand pieces. And still, even if the Nationals have wrested power away from the Phillies in the standings, they keep losing to them on the field.

Tuesday night, Nationals fell, 6-3, their fourth consecutive loss to the Phillies and eighth in 13 games. The Phillies took control with five runs off left-hander Ross Detwiler in the first three innings, including four in the third. The Nationals still have five more meetings to rectify their season series, but for now the Phillies lean on their showing against the 93-win Nationals as a means to salvage an (almost) lost season.

The Nationals came here with a chance to clinch during their series at Citizens Bank Bark. Now, though, the potential payback for the Phillies clinching three of their five division titles with victories over the Nationals is impossible.

“It could have been a big step,” Detwiler said. “We could have celebrated on their field like they celebrated on our field. I didn’t let that happen.”

The Nationals moved no closer to clinching the National League East, their magic number saying at five as the Atlanta Braves beat the Miami Marlins with a walk-off home run. The Nationals lead the Braves by four games with eight games remaining, still a commanding lead even if the Braves haven’t been so close to the Nationals since Aug. 8.

The Nationals also fell into a tie with the victorious Reds for the top seed in the National League and the best record in baseball.

“The worst thing you can do is look at the standings,” said catcher Kurt Suzuki, who went 3 for 4 with an RBI single.

“I’m not sure that people are really thinking about what’s ahead,” shortstop Ian Desmond said. “Honestly, getting the vibe in here, everyone is pretty focused on today. There’s enough to worry about today. Let tomorrow worry about itself.”

The Nationals made Phillies ace Cole Hamels throw 99 pitches through five innings. They remembered to work the starter, but they forgot to punish the middle relief. The Phillies’ bullpen had its way with the Nationals, five relievers retiring 12 of 13 hitters while allowing only two balls out of the infield.

The Nationals played from behind almost all night after Detwiler pitched as if under an evil spell in the third inning. Darin Ruf had drilled a homer, his first major league hit, off Detwiler to tie the score at 1 in the second. For a left-hander with a 2.76 ERA since the all-star break, one bad pitch could be explained. The depths Detwiler reached in the third were hard to figure.

Detwiler led off the inning with consecutive walks, which sent pitching coach Steve McCatty to the mound like Pavlov’s dog at the ring of a bell. Detwiler had walked three in the first two innings, including one free pass to Hamels.

“That loss is completely on me there in that second and third inning,” Detwiler said. “I was out there throwing the ball in the other batter’s box. It wasn’t even close. You can’t even expect a swing-and-miss at that point.”

In recent starts, Detwiler has thrived on mixing in more change-ups and curveballs to go with his diving sinker and mid-90s four-seam fastball. Tuesday night, unable to find the strike zone, getting behind in the count forced him to largely abandon his off-speed pitches.

“It gets tougher,” Suzuki said. “When you’re not accustomed to throwing off-speed pitches for strikes, it definitely gets a little tougher. You don’t want to throw them behind in the count. He’s been so good. You move on , put this one in the past.”

After McCatty retreated to the dugout, Ryan Howard singled home one run. Carlos Ruiz unloaded on a fastball down the chute, launching Detwiler’s first-pitch, a 91-mph sinker, into the left field seats for a three-run homer.

“It was embarrassing,” Detwiler said.

The Nationals trailed, 5-1, after three innings against Hamels, but their lineup makes that a manageable hurdle rather than a complete obstruction. The hitters at the top of the order get on base, the middle drives in runs and the bottom serves as pests. A rally may spring forth from anywhere, including the eighth spot. Suzuki smacked a leadoff single in the fifth, a spark that set up the rally that pushed the Nationals back into the game.

With two outs and Suzuki on second, Bryce Harper swatted a single into center field. John Mayberry charged and fired home. Harper never slowed down, taking second as Mayberry’s throw hopped home far too late to nab Suzuki. The extra base allowed Harper to score on Ryan Zimmerman’s RBI single to left field.

“It’s a tough lineup to pitch to,” Manager Davey Johnson said. “I know the problems that the opposing manager is looking at our club, and how they want to attack it. And it hasn’t been easy for them. It’s just a tough, solid lineup.”

Detwiler’s struggles in the third appeared even more peculiar when snapped out of it, retiring nine straight after Ruiz’s home run to finish his outing. The Nationals had cut their deficit to 5-3, but just as quickly as their offense revved up, it shut down.

The Nationals still have five more chances to beat the Phillies, to make sure the team that lorded over them for five years does not complicate their turn to reign.

“All year long, we haven’t liked losing,” Desmond said. “That’s how we got in the position we’re in now. But we’ve played up to this point. Today was just one of those lull games.”