Phillips' second slam in 11 days put John Maine in a four-run hole before he retired a batter. Phillips added an RBI double in the fifth and a run-scoring single in the sixth, matching his career high for RBI.
"His offense, his defense, both have been extremely impressive," Mackanin said. "He can run, he looks like he loves to play -- I'd take nine of him."
Frustrated by their underachieving offense, the Mets promoted Howard Johnson to hitting coach before the game and made Rickey Henderson their new first-base coach. The moves came after hitting coach Rick Down was fired during the All-Star break.
Lastings Milledge homered late for the NL East leaders, who dropped to 3-7 in July. After the game, Maine admitted he was unprepared coming out of the All-Star break.
"I didn't feel good all game. I didn't prepare at all. I didn't use the time. It's just bad," he said. "I felt out of whack, out of sync. My windup was bad, breaking ball was bad, changeup was bad."
Phillips and the Reds took advantage. The second baseman also made an outstanding defensive play and scored twice. He has 13 RBI during his nine-game hitting streak.
"The thing about him, he's not scared. He'll take down the challenge," Mackanin said. "He just did a little bit of everything. What a night for him."
Phillips' all-around performance made it an easy night for Harang (10-2), who struck out eight in six innings to win his fifth straight decision. Alex Gonzalez added a two-run single and the Reds (37-53) improved to 6-2 since Mackanin replaced the fired Jerry Narron on July 1.
"Pete's doing a great job. He's just letting everybody go out there and play," Phillips said.
Ryan Freel opened the game with a double, Norris Hopper reached on a bunt single and Ken Griffey Jr. walked to load the bases. Phillips drove the next pitch over the left-field fence for his 18th home run of the season and third career slam. He also hit a grand slam July 3 against San Francisco.
"To tell you the truth, I'm just happy to have a job. Hitting fourth is a privilege," Phillips said. "I was looking for a get-me-over slider and he threw it."
After that, Maine (10-5) kept Cincinnati at bay until the fifth, when two errors by second baseman Ruben Gotay led to three unearned runs. Gonzalez's two-run single with two outs made it 7-1 and chased Maine.
The right-hander, who had won four consecutive starts, gave up a season-high seven runs -- four earned -- and six hits. He walked three.
It matched the shortest outing of the year for Maine, who also went 4 2/3 innings on April 9 against Philadelphia -- New York's home opener.
"You have your best guy out there and all of a sudden he can't find the strike zone, he's behind the hitters and it's 4-0. We can't expect our best guy to have it every day," Mets slugger Carlos Beltran said.
Like Maine, Harang was left off the NL All-Star team despite a strong first half. He allowed three runs and seven hits, walking two.
"This game belongs to Harang. He's an All-Star in my book," Phillips said.
Gotay hit an RBI double in the third for the Mets, who loaded the bases with one out before Paul Lo Duca bounced into a double play.
"That was really huge in that situation, got us out of a possible inning that could've been really bad," Harang said. "You always feel good when you can go out without your best stuff and beat a team like them."
Harang became the first Reds pitcher to start 10-2 since Steve Parris in 1999.
"He throws, like, a sneaking fastball. I think he's underrated," Beltran said.
- Phillips also had six RBI on April 20, 2006, at Milwaukee.
- Mets LHP Tom Glavine goes for his 298th win Saturday night.
- Mackanin said he wants to rest Griffey one of the next two days.
- New York's home game against St. Louis that was rained out June 28 was rescheduled for Sept. 27 at 7:10 p.m.
- Rookie RHP Mike Pelfrey relieved Maine, the first relief appearance of Pelfrey's professional career.
- New York's bullpen had pitched 21 consecutive scoreless innings before Pelfrey allowed a run in the sixth.