MLB.com's No. 2 overall prospect went deep and drove in four runs for the second straight game, including with a three-run walk-off shot in the ninth inning, to give Scottsdale an 8-7 win over Mesa.
"It was 3-1 and they had a base open," said teammate Mike Trout, baseball's top overall prospect. "I had figured they wouldn't throw him one. They threw it right down the middle and he put a good swing on it. It was hit pretty well. The wind was blowing in a little bit, and he hit it pretty hard to get it out of here."
The first overall pick in 2010, Harper has batted .387 (12-for-31) over his past eight games, collecting three homers and 13 RBIs. After recording just one hit in his first five contests, the 19-year-old Nationals outfielder is now hitting .260.
"He's doing well," Trout said. "He's taking it pitch by pitch, that's the main thing. He sometimes swings at bad pitches and he makes adjustments. That's the big thing I've seen. He's making adjustments like everyone else."
Trout and fellow Angels prospect Jean Segura both tallied three hits at the top of the Scorpions order, totaling one fewer than the rest of the team combined. Trout doubled and scored, raising his batting average to .278.
"I've been trying to get deeper into counts, just trying to get some balls up," he said. "A couple fell in for me today -- I hit one of them hard. I'm just trying to have good, quality at-bats and go out there and have some fun. And win a game once in a while."
Segura tripled, stole a base, drove in two and crossed home twice. After playing in only 52 games this year due to hamstring injuries, the Halos' No. 3 prospect is now batting .356 in 12 AFL games.
"He's swinging the bat well, not chasing pitches," Trout said. "He's got a good swing. He's been hurt all year. It's disappointing to me because he's a good player. He's getting more quality at-bats and will go from there."
Xavier Avery led the way for Mesa, collecting three hits and drawing a walk while plating two. A second-round pick in 2008, the 21-year-old outfielder has accumulated 11 hits in his last seven games. With that hot streak, he has lifted his average from .071 on Oct. 17 to .241.
"When I first got here, I was facing a lot of lefties, so I had to make some adjustments," said Avery, who bats and throws left-handed. "I feel like I've made those adjustments, and I've had a better approach at the plate."
Top Twins prospect Aaron Hicks also recorded three hits for the Solar Sox, doubling twice with three runs and two RBIs.
David Heck is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.