PHILADELPHIA -- Nick Castellanos has a way of putting things, so it’s no surprise that he captured the vibes this week at Citizens Bank Park.

“It definitely feels like October is around the corner,” he said.

Castellanos hit a game-tying two-out, two-run double to left-center field in the sixth inning and a two-out walk-off single to center in the 11th to beat Atlanta, 3-2, on Sunday night at Citizens Bank Park. The Phillies won three of four in the series to take a seven-game lead over the Braves in the National League East with 25 games to play.

“We still have to solidify our spot where we want to be for October,” Castellanos said. “We had a successful series. No question it was big, but there’s still a lot of baseball left before the playoffs.”

The math is in the Phillies’ favor to win their first division title since 2011. Even if they play a game under .500 the rest of the season, they would finish 93-69. The Braves would need to finish 19-6 (.760) to tie them, which would give Atlanta the division because it holds the head-to-head tiebreaker by winning the season series.

But the Braves have not had a better 25-game stretch than when they went 18-7 at the beginning of the year when they were at full strength. And the Phillies have no plans to play under .500 the rest of the way.

“We’ve got to keep going,” manager Rob Thomson said. “I’ve seen it in the past where you have a big series and there’s a letdown. You can’t let down. You’ve got to keep going. You’ve got to keep fighting.”

These two teams could meet again in October. It would be fun. Atlanta has won the past six NL East titles, but it lost to Philadelphia in each of the past two postseasons.

Don’t think the Braves would love a little October revenge?

Don’t think the Phils would enjoy the opportunity to win three consecutive postseason series against their division rivals?

“We’re just two really good baseball teams, right?” Castellanos said.

Castellanos was in the middle of everything this week in series victories vs. Houston and Atlanta. He hit a three-run homer against Astros right-hander Justin Verlander in a 5-0 victory on Tuesday. He hit a go-ahead two-run homer against the Braves in the seventh inning in a 5-4 victory on Thursday.

He came up big again on Sunday.

Braves rookie Spencer Schwellenbach broke the bats of three consecutive Phillies in the fourth and fifth innings, including Castellanos in the fourth. It appeared to be more of the same from the right-hander, who had dominated the Phils through 17 2/3 innings over three starts, allowing only three runs, when he entered the sixth inning on Sunday.

But then Schwellenbach allowed a two-out single to Trea Turner and a bloop double to Bryce Harper to put runners on second and third. He quickly got 0-2 on Castellanos.

Entering Sunday, Castellanos had batted .145 (9-for-62) with 27 strikeouts and a .334 OPS in 0-2 counts this season. The average MLB hitter has hit .150 with a .382 OPS.

Schwellenbach tried to throw Castellanos a slider down and away. Instead, he badly missed his spot. He threw it up and into the strike zone instead.

Castellanos took advantage. He hit the ball to left-center to score Turner and Harper to tie the game.

Braves closer Raisel Iglesias struck out a jumpy and aggressive Castellanos on three pitches in the ninth. The slugger said he wasn’t going to make that same mistake again.

He got another opportunity in the 11th.

Grant Holmes, who allowed Castellanos’ homer on Thursday, got ahead of him 0-2. But he threw him a 1-2 fastball down the middle of the plate.

Castellanos ripped it.

“It makes me want to have two strikes more often,” Castellanos said, smiling.

Carlos Estévez pitched two perfect innings in the 10th and 11th with the automatic runner on second base. He struck out Whit Merrifield swinging on a 97.9 mph fastball to end the top of the 11th, stranding the go-ahead runner on third.

Estévez said he loved the atmosphere this weekend. He has pitched only one-third of an inning in his postseason career. He should get another taste this October.

Maybe he will see the Braves again.

"We don't get cold feet, that's what it looks like,” Estévez said about the Phillies-Braves rivalry. “That's a really good thing to have a group of guys like this that can go against anyone on the other side and compete like that. I really like that."