Kepler, the Twins' No. 8 prospect, drove in the Desert Dogs' first two runs with a bases-loaded double in the fourth inning and finished the night 2-for-4 with two runs.
Three of Kepler's at bats came against left-handers, including Salt River starter Grayson Garvin. Kepler, a left-handed batter, said he was happy with his approach against them.
"I was seeing the ball well," Kepler said. "I'm getting my knocks and doing what I can."
Kepler outplayed his higher-profile Twins teammates Wednesday. Center fielder Byron Buxton, baseball's top prospect, went 0-for-3 with two walks, a stolen base and a run. Second baseman Eddie Rosario, the Twins' No. 5 prospect, went 0-for-4 with an RBI.
Kepler said having his Twins teammates with him in Arizona has made him more comfortable.
"It's like family," Kepler said. "I love having them around. They're all great players. It makes it easier to adapt."
In addition to Kepler, Glendale's offense got a boost from catcher Pratt Maynard. He hit a three-run home run in the sixth inning, helping to stave off Salt River's comeback.
The Rafters were led by designated hitter Stephen Piscotty. The Cardinals' No. 7 prospect went 2-for-4 with a double, a triple and two runs. After going 1-for-11 with six strikeouts last week, Piscotty has found his swing and is 8-for-12 in three games this week.
Left-hander Andrew Heaney wasn't as electric as he was when he struck out six batters in three innings in his AFL debut last week. Against Salt River, the Marlins' No. 2 prospect allowed two runs on four hits in 3 2/3 innings. He struck out two batters and walked a pair.
But Heaney and Glendale were able to beat Garvin, who also was better in his first outing of the fall. He threw five scoreless innings last week, but allowed four runs (three earned) in four innings against Glendale.
Still, Garvin impressed Kepler.
"He's good, like every other one of those lefties," Kepler said. "I had heard a lot of stuff about him and he's got some good stuff, definitely."
While Kepler is working to improve at the plate this fall, his main focus is on defense and getting stronger. The Twins moved him from the outfield to first base this season, and he is still working to get comfortable at his new position.
"I thought it would take me a while, but with the ground balls coming at me, I'm good with all that," Kepler said. "I'm still trying to memorize all the situations, because there are a lot of them, like all the bunt plays. But I'm definitely feeling good, confident."