Phipps broke out of a season-long slump with five hits and drove in four runs, leading the Triple-A Louisville Bats to a 22-1 romp over the Gwinnett Braves.
After singling twice in a six-run opening inning, the native of the Dominican Republic capped a seven-run second with a grand slam, extending the Bats' lead to 13-0 lead.
Phipps singled in the fourth and walked and scored his third run of the night in the sixth before striking out in the seventh. He singled again in the eighth, establishing a career high for hits in a game.
"I felt good," said Phipps, who turns 27 on July 22. "When the guys get on, it gets you a lot of confidence and shows that you can do it."
The 2011 Southern League All-Star has been struggling all year, with Friday's performance raising his average to .180 to go with six homers and 25 RBIs in 48 games. It's been a new experience for the outfielder, who entered the season with a .262 career mark.
"It's been a frustrating year for me. I've been injured two times," Phipps said. "I'm trying to do everything I can to help my team win. We've struggled since the beginning of the year. Everything I can do, I'm going to do it.
"Every swing I did good, I'm going to do tomorrow. Everything I did well, I'm going to try and do every time at the plate."
Neftali Soto, the Reds' No. 6 prospect, homered, doubled and drove in five runs.
"He's one of the good hitters we have," Phipps said. "He's the guy -- when he starts hitting, he can carry the team."
The Bats fell a hit shy of the club record, set on May 3, 2010. They slugged two grand slams in a game for the first time since 2007.
"It's fun," Phipps said. "Every time you win, it's fun. We've trying to be aggressive on the bases and be aggressive hitters and everything was going good tonight."
Didi Gregorius, Cincinnati's No. 4 prospect, collected three hits in his second Triple-A game. Cody Puckett homered and drove in four runs, while Chris Valaika entered in the seventh and contributed Louisville's second slam.
Staked to a huge early lead, Bats starter Sean Gallagher improved to 7-6, allowing a run on five hits over six innings.
Braves starter Yohan Flande (3-7) did not survive the first inning. He surrendered six runs on seven hits while recording two outs and lost his third straight decision.