Arenado started out the night with a bases-loaded single in the first that plated a pair. He added a sacrifice fly in the third, followed by RBI singles in the eighth and ninth.
"My whole goal is driving the ball hard up the middle," he said. "Whatever these pitchers are throwing, I've got to make adjustments. Just hit the ball hard and see what happens."
Drafted in the second round in 2009, Arenado hit .298 with 20 home runs in 134 games for Class A Advanced Modesto. Through five AFL games, the 20-year-old third baseman is batting .381 (8-for-21) and is tied for the league lead with nine RBIs.
"This is an honor," he said. "I'm very excited the Rockies let me come here and let me show what I can do. If you can hang with these guys, you never know what can happen [in terms of] making it to the big leagues."
As far as driving in runs, Arenado credited the strong teams he has played for. The Nuts went 74-66 en route to a playoff berth, while the Rafters stand first in the AFL East with a 6-2 record.
"People are getting on base and giving me opportunities to drive people in -- that's all it is," he said. "I'm trying to slow the game down with men on base and do what I do."
Alex Castellanos (Dodgers) also had a strong game for the Rafters, going 3-for-3 with a double, two walks and scored four times. Adam Eaton (Padres) went 2-for-4 with three runs.
Reliever Eric Smith (D-backs) earned the win by striking out two over two shutout innings, while Andrew Taylor (Angels) took the loss after yielding four runs on 3 hits in 1 1/3 frames.
Angels shortstop Jean Segura went 3-for-4 with an RBI and a run scored for Scottsdale. He is batting .385 in four games.
Asked whether he was working on anything in particular in the AFL, Arenado replied, "Everything."
"Hitting -- these pitchers are good, so you're trying to see yourself compete with these guys. Timing, infielding, range. I'm happy so far, I've been playing well. This was a long year and now it's more baseball, but it's a great honor to be here and I'm very excited. It's a lot of fun."