Soriano hit a solo homer with two outs in the third, a leadoff homer in the fifth, and a three-run shot with two outs in the sixth. It's the third three-homer game of his career, and first since June 8, 2007, at Atlanta.
"It feels good," Soriano said. "It's a very special day for me."
He finished with four hits, four runs and several standing ovations from the Cubs fans in the sellout crowd of 41,204 at Great American Ball Park. Soriano joins Aramis Ramirez, Sammy Sosa, Dave Kingman, Ernie Banks and Hank Sauer as Cubs players with multiple three-homer games.
Piniella tried to get the offense going by inserting rookie Micah Hoffpauir in right field in place of Kosuke Fukudome. Soriano was in a mini funk of his own, batting .131 in his last eight games, and snapped out of that when he launched his 25th home run in the third. He was just getting warmed up.
Chicago added a run in the fourth on Hoffpauir's ground out. The Reds loaded the bases with two outs in the fourth and Marquis fell behind 3-0 to Chris Dickerson, then threw what he thought was a strike. Home umpire Brian Runge saw it differently, and Dickerson walked to force in a run.
"I was a little emotional," Marquis said. "I wanted [the call]. It's no disrespect to the umpires. I had to settle down and make pitches, and I was able to do that."
"I told Marquis, I said, 'Don't get the umpire upset,'" Piniella said. "You don't want to be squeezed."
Soriano, who finished the night with four hits, made it 3-1 with his second homer in the fifth off Reds starter Johnny Cueto (8-13). DeRosa walked, and Reed Johnson singled to set up Soriano's third long ball in the sixth off Jared Burton. DeRosa also connected off Burton in the seventh with two on and two outs.
With his career highs of 20 homers and 83 RBIs, DeRosa may never see Tucson again.
"He was asking me about the Tucson trips all the time. I said [this spring], 'If you hit 20 home runs and drive in 80 runs, you won't have to go to Tucson,'" Piniella said. "Well, he's done it."
Soriano also may have earned himself the day off when the Cubs make that two-hour bus ride for Cactus League games, as well.
"When he hits, our team seems to really respond and do well," Piniella said of his leadoff man. "A lot of teams are that way -- when the leadoff hitter sets the tone, it's a catalyst for the offense. Today was no exception."
"I come to the game every day with the same energy, try to win and do the best I can," Soriano said. "I didn't lose my confidence, I didn't lose my concentration. That's most important.
"I keep in my mind it's a long season, and I cannot be perfect every day," he said. "Some days, I can be struggling, but I'm working hard, and I get out of the slump to do the best I can to win."
It's not as if Soriano tries to shoulder the load.
"This game isn't like basketball," Soriano said. "They depend on me, but there are nine players on the field. Especially this team, we have eight good players who can carry the team -- we have [Geovany] Soto, D-Lee, Aramis. When I'm struggling, they can carry the team, too. I don't have to do it every day."
But in September 2007, it seemed as if Soriano was doing it every day, hitting 14 homers that month and batting .320.
"I remember last September, but that's in the past," Soriano said. "This is a new September. It's more important for me to stay healthy and try to help the team to win."
"I hope he gets another big September," Piniella said. "We need it."
Marquis (10-8) gave up two runs, five hits and five walks and struck out two over 7 1/3 innings, his longest outing of the season. He also hit a leadoff homer in the eighth, the fourth of his career. The five homers by Chicago is a season high.
"I feel good with where I'm at," Marquis said. "I'm trying to get consistent with my stuff and working hard."
The Cubs' bullpen needed all the runs as the Reds tacked on eight runs after Marquis exited, including four on Jolbert Cabrera's grand slam. Birthday boy Derrek Lee had two hits and three RBIs for the Cubs, who maintained a four-game lead over the Milwaukee Brewers in the National League Central.
"We needed a win," Piniella said, "and we got it."