PHILADELPHIA -- Bryce Harper always wanted to play a baseball game on his birthday. So he made sure his 31st was one to celebrate.

Harper crushed a 420-foot first-inning home run, blew out his "candles" as he crossed home plate, lined an RBI single in the third inning, walked and scored in the fifth inning, received chants of "M-V-P!" and was serenaded with a couple of "Happy birthday!" shoutouts from the home fans. With Harper leading the way, and with the Philadelphia Phillies delivering an early burst of home runs, they beat the Arizona Diamondbacks 5-3 to win Game 1 of the National League Championship Series on Monday night.

"After the game, I was pumped, just being 1-0. That's all I care about. Good opportunity to hit a home run, that was great, but at the end of the day, if I hit a homer and we don't win, there's nothing else," Harper said, much more subdued postgame than during his home run celebration, when he blew on his fingers at home plate after he gave the Phillies a 2-0 lead off Zac Gallen just five pitches into the bottom of the first.

"It's crazy. Sometimes I just do stuff. That felt right, step on home plate and do that," Harper said. "I thought about it as I was running around third base."

Harper spoke before the game about being excited to finally play on his birthday. He made the playoffs four times with the Washington Nationals, but they were eliminated each time in the division series and never played this late in the calendar. The Phillies were still playing last year during their World Series run but had an off day.

Harper's big day was just the latest in his hot postseason. The home run, off a first-pitch four-seam fastball from Gallen that was left over the middle of the zone, was his fourth, and he's hitting .409/.567/.955 with nine runs scored in seven games. His career OPS in the postseason now ranks third all time behind only Babe Ruth and Lou Gehrig among players with at least 150 plate appearances.

The scary thing for the Diamondbacks: Harper might not even be the Phillies' hottest hitter. Nick Castellanos gave them a 3-0 lead with a second-inning home run off Gallen, following the first-inning blasts from Kyle Schwarber and Harper. It was Castellanos' fifth home run over three postseason games -- tying Reggie Jackson's mark from the 1977 World Series, when he homered once in Game 4, once in Game 5 and three times in the Game 6 clincher for the New York Yankees.

"It makes our lineup so deep, especially him in the seven-hole or eight-hole, it just gives him a good opportunity to have success," Harper said. "Whenever he's staying on the baseball and driving the ball to right-center and hitting the curveball or hitting the heater to left, that's how Nicky is. He's come through in so many big spots."

The Phillies also set a postseason record with 12 home runs over three games and now are hitting an impressive .275/.355/.550 with 16 home runs in those seven games while averaging 5.1 runs per game.

"I am amazed. Not surprised," Castellanos said.

The difference?

"When you're watching something amazing like all these home runs we're hitting, you can appreciate it," he said. "But I'm not surprised because I know we're capable of doing it."

Castellanos said he wasn't interested in tying Jackson's mark.

"I'm interested in winning seven more games," he said.

After the Phillies jumped all over Gallen, starting pitcher Zack Wheeler took over in leading Philadelphia's efforts, retiring 15 in a row until Geraldo Perdomo touched him for a two-run home run in the sixth. Wheeler improved to 2-0 in three starts this postseason with a 2.37 ERA, 37.7% strikeout rate and just one walk. His fastball command continues to impress: He threw 17 first-pitch strikes out of 21 batters faced and induced 17 swings and misses while recording eight strikeouts.

"It had good life," Wheeler said about his fastball. "Threw it basically where I wanted to."

The early lead certainly helped.

"In the playoffs, everything is amplified. That early momentum was big for us," he said.

Game 2 is Tuesday night with the Diamondbacks' Merrill Kelly facing the Phillies' Aaron Nola.