Whitaker slugged a career-high three homers and drove in seven runs as Class A Advanced Stockton routed San Jose, 15-4.
The 2010 25th-rounder by the Athletics went deep with a man on base in the first inning and followed that up with another two-run blast in the second. After fanning in the fourth and walking in the sixth, the Georgia native capped his night with a three-run blast with two outs in the eighth.
"I was just getting good pitches to hit and making them come to me, not chasing anything out of the zone," Whitaker said. "Not getting into terrible counts and putting a good swing on it. I was just thinking about hitting it hard and I got it up a little. My approach today was to hit it hard."
"It is very exciting. It's not something you go to the park thinking about doing. You don't just wake up thinking you're going to hit three homers. I'm still kind of enjoying it right now."
Whitaker had never homered twice before in a pro game and had five RBIs for Burlington on July 1, 2011. The 23-year-old outfielder was excited about his performance, but had more work ahead of him.
"I'm feeling great, I just have to write a 10-page paper I'm a little bummed about it," said Whitaker, who is finishing up a degree in education.
Whitaker became the fourth California League player to homer three times in a game this season and the second member of the Ports to do so. A.J. Kirby-Jones managed the feat April 18 in the Ports' 8-0 win.
"It is now," Whitaker said when asked if there was a new rivalry. "I told him [Kirby-Jones] in the dugout that I wanted to be just like him. We have a little joke going about it now."
Overall, Whitaker is batting .273 with 11 homers and 34 RBIs in 66 games for Stockton.
Chad Oberacker smacked an inside-the-park homer and plated three runs for the Ports, and B.A. Vollmuth scored three times.
Josh Bowman picked up his second win after allowing an unearned run on two hits while fanning five over seven innings.
Alex Burg slugged a two-run homer in the ninth for the Giants.