ST. LOUIS — Prince Fielder beat the hometown boppers on their own turf.

With Albert Pujols and Ryan Howard eliminated early, Fielder won baseball’s Home Run Derby on Monday night with a steady power display that included a jaw-dropping drive estimated at 503 feet.

The Milwaukee Brewers’ first baseman outslugged Texas outfielder Nelson Cruz 6-5 in the finals at Busch Stadium to take home a title that St. Louis fans surely hoped would go to one of their own.

‘‘It’s what I expected. This is Albert’s stadium and Ryan is from here,’’ Fielder said. ‘‘I was just happy I was able to put on a show and I’m glad I won.’’

Pujols, the Cardinals’ big first baseman, and Howard, who grew up in the Gateway City and plays for the Philadelphia Phillies, were knocked out in the second round.

‘‘I wish I would have put a better show for our fans,’’ Pujols said. ‘‘I was nervous a little bit.’’

This year’s All-Star festivities were supposed to belong to Pujols in his home ballpark. But Fielder snatched the spotlight in the annual warmup for Tuesday night’s Midsummer Classic.

With three outs remaining in the final round, Fielder smacked a drive onto the grassy hill in center field to clinch the crown. He posed for a moment with his bat held high, then embraced Brewers teammate Ryan Braun near home plate.

Fielder started out using a bat that belonged to injured Milwaukee teammate Rickie Weeks, then switched to Braun’s stick.

‘‘It was a little longer,’’ Fielder said. ‘‘Once I grabbed his bat, it felt pretty good.’’

Fielder, the son of former big league slugger Cecil Fielder, became the youngest player to hit 50 homers in 2007 at age 23. But that season, he was eliminated in the first round of the Home Run Derby at San Francisco.

‘‘I knew what to expect this time so I was a little more relaxed,’’ he said. ‘‘I think it’s very competitive. I don’t think (any) of the guys would be here if they weren’t. But it’s fun at the same time.’’

Fielder and Cruz both made their major league debuts in 2005 with the Brewers — and each has 22 home runs this year. Cruz, enjoying a breakout season, was a late addition to the All-Star roster because of an injury to Los Angeles Angels outfielder Torii Hunter

Pujols, who leads the majors with 32 homers, needed a late rally just to avoid elimination in the first round. With one out to work with, he connected on consecutive swings to force a three-player swing-off for the final spot in round 2, sending the red-clad crowd of 45,981 into a high-fiving frenzy.

One fan in the bleachers lent a helping hand, too, appearing to reach over the right-center fence to catch one of Pujols’ homers. During a game it might have been ruled fan interference, but there’s no video replay in the derby.

Carlos Pena hit one homer in the five-swing tiebreaker and Joe Mauer was shut out. So when Pujols homered twice he moved on — but not for long.

Looking fatigued, he managed six homers next time up for a two-round total of 11, easily surpassed by Fielder, Cruz and Howard, the 2006 derby champ.

‘‘I didn’t feel any pressure. I mean, I think the only pressure you feel in a Home Run Derby is that you just want to try and get at least one,’’ said Howard, who picked an old favorite for his batting-practice pitcher. ‘‘It was a lot of fun for me to have my summer ball coach (Deron Spink) out there because it was a special experience for him. It meant more to me to have him out there than just about anything else.’’

Pujols failed to come through for a fan right before the contest. With a chance to win an attractive prize package, Mark Weinberger of Philadelphia pointed to left field a couple of times — calling Pujols’ shot.

Alas, the two-time MVP was unable to clear the fences. Still, after his final swing in the derby, Pujols received a warm ovation.

‘‘Thank you so much for your support,’’ he told the crowd.

Fielder hit the longest shot of the night, a 503-foot drive to right-center that disappeared between two sections of bleachers.

‘‘I’m just happy. It was pretty cool to actually win one,’’ Fielder said before explaining his hitting philosophy. ‘‘I’m not quite sure about my mechanics. I just know I have to swing hard. In high school a lot of people told me to swing easier and everything, but I just don’t know how to do that.’’

During the first round, Cruz hit a drive into the fourth deck in left field, never accomplished during a game at 4-year-old Busch Stadium.

Brandon Inge, Adrian Gonzalez, Pena and Mauer were knocked out in the first round. Inge, the Detroit Tigers’ third baseman, became the eighth contestant to get shut out since the current format was adopted in 1996. Jason Bay was the previous one in 2005.