"I got a good pitch to hit and it went over the wall," Harper said of the 1-0 fastball he deposited over the center-field wall. "[Gilmartin] has a good slider and curve, so I was looking to jump on his fastball or cutter early. I tried to hit it into the gap, but it went a bit further than that.
"I'm feeling pretty good up there. I'm not trying to get too big, I'm just trying to swing the bat well and get some hits."
Harper's success in Arizona is a promising sign to Nationals fans and scouts alike after the 19-year-old outfielder had his first full season in the Minors cut short by a hamstring injury. He missed the final few weeks of the season with Double-A Harrisburg, but has responded well since joining Scottsdale -- he's batting .323 with 21 hits and three steals in 17 games.
"I definitely am maturing," Harper explained. "I'm trying to learn from the older guys like [Brandon] Crawford and that has been huge. I'm learning when to run and not to run, I'm learning to see better pitches and I'm busting my butt every day.
"I'm trying not to chase pitcher's pitches, and when I get into an 0-2 hole, I'm learning how to battle. You can always improve every day."
Cody Overbeck (Phillies) homered and knocked in three runs and third baseman Ryan Dent (Red Sox) plated two for the Scorpions. Giants first-rounder Joe Panik went 4-for-5 with a double, raising his average to .295 in the victory, and Crawford extended his hitting streak to 12 games with a first-inning ground-rule double.
Zach Walters (Nationals) was 2-for-3 with two runs scored off the bench in place of fellow Phillies prospect Darin Ruf, who drove in two runs but left the game in the third frame after trying to beat out a ground ball to shortstop Tim Beckham.
"Walters came in and swung it well after Ruf got injured, and Crawford has one or two hits every single day," said Harper, who headlines a list of prospects competing in Saturday's Rising Stars Game. "We're pretty good one through nine."
Boston's Jeremy Kehrt (1-0) started for Scottsdale and allowed a run on two hits over two frames. He struck out a pair and did not walk a batter.
Marlins outfielder Kevin Mattison, who hit a walk-off homer in his last game Nov. 1, added his fourth home run in the fifth inning, a two-run drive off lefty Will Latimer (Red Sox). Cleanup hitter Mike Olt (Rangers) hit his AFL-leading seventh dinger in the second off Kehrt.