WASHINGTON (AP) — The first boos, guttural and loud in a mostly empty ballpark, greeted Bryce Harper during pregame introductions 15 minutes before the rain-delayed first pitch Tuesday night, as he stood in the Nationals Park visitor's dugout wearing another team's uniform.Jeers again filled the chilly air when Harper walked to the plate as the No. 3 hitter for the Philadelphia Phillies in the first inning, his initial at-bat as a Nationals opponent. More hostility came while he awaited each pitch from Washington's Max Scherzer, negativity interrupted only by the sheer-joy roars after each strike of his eventual whiff, which concluded with a swing-and-miss at an 85 mph changeup.Harper had said he expected a mixed reaction from spectators in his return to D.C. after leaving via free agency to sign a $330 million, 13-year deal with the Phillies. Sure sounded rather one-sided from an announced attendance of 35,920.Adding to the theatrics of it all, as is his wont, Harper delivered a no-doubt-about-it homer into the second deck off Jeremy Hellickson in the eighth inning, a two-run shot that traveled about 450 feet and put the Phillies ahead 8-2. That topped off a 3-for-5 showing with three RBIs, and Harper marked the moment with an epic, twirling bat flip in the direction of his former dugout, followed by elaborately choreographed celebrations with his current teammates .In the bottom half of the first, there was booing as Harper headed out to play right field — where fans in the front row of the bleachers wore shirts that spelled out "T-R-A-I-T-O-R" — and when he caught Adam Eaton's fly for the first out.After Ks in his first two at-bats, Harper doubled off Scherzer in the fifth, then singled in a run off lefty reliever Matt Grace in the sixth. He reacted to both with an exaggerated wave toward the Phillies' dugout. Fans who made the trek down I-95 from Philadelphia regaled him with chants of "M-V-P!" and "We got Harper!"Hours earlier, wearing a black baseball hat with "Positive Vibes" stitched in white and an attitude to match, Harper described his arrival this way: "Just coming to another stadium, and try to do my job."Truthfully, of course, it's not just ANY other stadium. That he was speaking at the unusual-for-baseball pregame news conference packed with reporters, photographers and TV cameras was testament to that.Until last week, the Nationals were the only big league club the 26-year-old Harper had played for, an organization that drafted him No. 1 overall in 2010 and brought him to the majors as a teen. Washington's uniform was the one he wore when he won NL Rookie of the Year and MVP honors, when he earned six All-Star selections in seven seasons — including last year, when he stole the show by winning the Home Run Derby in D.C."It's where," he said, "I grew up."But the Nationals offered him less money than the Phillies did, with millions that would be deferred for decades. So he moved on.He posted a "Thank you" message Tuesday to Nationals fans and the city of Washington on Instagram. The only time Harper really betrayed a hint of real emotion before the game was when he choked on his words while talking about how he and his wife, Kayla, are expecting their first baby.Otherwise, he spoke about being "excited for the next chapter" and "pumped" to be back."I imagine it's got to be a little weird. A ton of emotions," Phillies first baseman Rhys Hoskins said. "Obviously he gave a ton to this organization. And he and Kayla gave a ton to this city. I hope people don't forget about that. It's been talked about for a while, too, so I'm sure there's a ton of buildup for him."After Harper's 15-minute session with reporters, he left the stadium's interview room. Instead of turning to his left to go to the home clubhouse, he walked to his right, down a hallway leading to the visiting clubhouse.Later, he hung out in the lunch room, chatting and laughing with Andrew McCutchen and two other Phillies.Across the ballpark, Nationals players spoke about the prospect of facing him instead of relying on him."For a lot of us in here, we've turned the page and we're focused on this season," closer Sean Doolittle said. "We've kind of come to grips with it."Or as first baseman Ryan Zimmerman put it: "Honestly, it's just another game."To him, maybe.To the Nationals supporters who paid for the right to boo when the guy who wore No. 34 for so long strode to the plate wearing his No. 3 Phillies jersey, probably not.___Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich___More AP baseball: https://apnews.com/MLB and https://twitter.com/AP_Sports