PHILADELPHIA >> Fresh from singing another rollicking chorus of “Fly, Eagles fly,” fans streamed out of Lincoln Financial Field on Sunday and quickly turned their attention from the NFL’s only unbeaten club to another Philly team, another sport and another building just a few hundred yards away.

“Let’s go, Phillies!” some chanted in the concourse. “Let’s go, Harper!” other hollered as they headed to the exits.

Think that was loud? Just wait till the World Series returns to Philadelphia for the first time since 2009. On Halloween night, too, with the Phillie Phanatic sure to be in rare form.

Already frenzied during the NL playoffs, Citizens Bank Park figures to be positively pulsating for Game 3 on Monday night — providing the rain that’s in the forecast doesn’t dampen things.

Noah Syndergaard is set to start for the Phillies against Lance McCullers Jr. and the Houston Astros with the Series tied at one game each.

“Philly fans are the best, they know the game. They just have a way of showing displeasure that sometimes is hard for players to understand,” Mike Schmidt, the greatest Phillie of them all, said in an email to The Associated Press on Sunday.

That’s certainly one way of putting it, coming from a three-time NL MVP and first-ballot Hall of Famer who heard boos often enough at Veterans Stadium.

Schmidt is widely expected to be at the ballpark for the pregame festivities when the Series resumes after a travel day. And he’s certain to draw a standing ovation and hear loud cheers — indeed, the City of Brotherly Love is in love with all of its Phillies these days.

At their ballpark, a large World Series banner was in place. Across the street, a giant “Let’s Go Phillies!” sign was draped from the Eagles’ stadium before they routed the Pittsburgh Steelers 35-13 to improve to 7-0.

McCullers says he’s eager to hear and see the whole scene.

“I have not been shy as far as just being open to pitching on the road. I think it’s really cool to pitch on the road in the postseason. I think it’s when you get to experience the most raw and real atmospheres in all the game,” he said.

Bryce Harper, Kyle Schwarber and the Phillies are all too eager to show the curveballing McCullers first-hand how quickly things can spin out of control in Philadelphia’s pinball machine.

After going 47-34 at the Bank this season — good, not great compared with several top teams — the Phillies have become monster mashers at home in playoffs.

Philadelphia went 5-0 at home in eliminating defending World Series champion Atlanta and San Diego in the playoffs, outscoring them by a total of 35-15.

Harper, Schwarber and Rhys Hoskins got the park bouncing with long balls. J.T. Realmuto thrilled a sellout crowd when his drive took a crazy carom off the oddly angled wall in center field, letting him become the first catcher in postseason history to hit an inside-the-park home run.

Philadelphia Flyers coach John Tortorella had just gotten out of his car at the adjacent Wells Fargo Center when the Phillies broke loose in a playoff game.

“It was shaking over where I was. That was pretty cool,” Tortorella said. “That’s what I love about being here.”

Syndergaard, who spent his first six seasons in the majors pitching for the NL East rival New York Mets, is glad he’ll be warming up for the home side.

“I never had the ability to play a playoff game wearing a Mets jersey in Citizens Bank Park,” he said. “But I’m more than happy and more relieved to be wearing a Phillies jersey down in that bullpen.”

“Because, I mean, those fans are on those guys from pitch one to the end of the game. And they’re an important part of this team and this organization as well,” he said.

Schmidt vividly recalled the Philly faithful heckling and taunting a Dodgers pitcher into a meltdown on the mound during the 1977 NLCS.

“They can affect what happens in the game, like the Burt Hooton debacle,” the former third baseman said. “They affect game momentum. I estimate an additional 20% advantage for home team in baseball.”

“They love when the players bring them into the game with emotion and acknowledgment,” he said.

Syndergaard, a fan favorite in New York with his flowing, blond hair that drew him the nickname “Thor,” has pitched three times in the postseason this year for a combined 5 1/3 innings. His last start came on Oct. 15 in the NL Division Series against Atlanta when he gave up one run in three innings.

Now, he’ll face Jose Altuve, Alex Bregman and manager Dusty Baker’s Astros, who scored five runs each off Phillies aces Aaron Nola and Zack Wheeler in splitting the first two games.

“Well, he hasn’t had a real start really since probably the middle of September, and probably his highest pitch count is like around 35 pitches,” Phillies manager Rob Thomson said.

“I think that three-inning mark is — probably three, four innings, is probably where we’re at,” he said.

Thomson will also keep an eye on the weather.

“They want to make sure that there’s no delays, that they got enough time to get it in,” he said.

“If it’s really light and misty and it’s not going to get any heavier, they may start it. If it’s going to be moderate to heavy rain, they won’t start it,” he said.