It was Soriano's 20th home run of the season -- the 11th consecutive year he has reached the mark, putting him in rare company. Boston's David Ortiz, Angels first baseman Albert Pujols and Soriano are the only active sluggers to reach the 20-homer mark for 11 straight seasons.
Soriano also joins Hall of Famer Andre Dawson as the only two players in Cubs history to hit at least 20 homers in their first six seasons with the club.
"I'm very happy for myself. I've never seen myself like a home run hitter, but 11 years in a row, 20 or more, I have to be very proud of myself," Soriano said. "Be proud because I've worked hard to help my team to win."
Cubs manager Dale Sveum agreed.
"I think that's something to be proud of," Sveum said. "Not too many people have hit 20 home runs 11 consecutive years. I'm just glad he did it with us."
Anthony Rizzo, who reached base a season-high-tying four times, drew a one-out walk against lefty Sean Marshall (4-4) in the eighth before Soriano, on the sixth pitch of the at-bat with rain coming down, belted right-hander Logan Ondrusek's offering.
"I've done well against him in the past. It's just tonight I didn't make my pitch," Ondrusek said. "He laid off a curveball in the dirt and fouled off some stuff down, so I thought if I elevated I could get it by him. I just didn't get it high enough, and he hit it out of the park."
Cubs closer Carlos Marmol worked the ninth to convert his 13th consecutive save, 14th overall, and preserve the win for reliever Shawn Camp (3-5).
Soriano's heroics came after the Cubs tied the game in the sixth by scoring two runs off Reds right-hander Mike Leake, who had held them to one in the previous five.
Darwin Barney knocked a one-out single and Rizzo followed with a walk before Starlin Castro laced a two-run double off the top of the center-field wall. The double was just Castro's second hit in his last seven games, a stretch in which he was batting .077 (2-for-26) and was moved down to the five-hole.
"That was huge," Sveum said. "Like I told him after the game: it's not how many hits you get, it's when you get them, especially when you're in that spot."
In a game that was delayed 1 hour and 20 minutes because of rain, Reds shortstop Zack Cozart gave Cubs starter Chris Volstad a rude welcome with a leadoff homer. The Reds added another run in the opening inning when Drew Stubbs walked, advanced to third and scored on a groundout by Ryan Ludwick.
Todd Frazier also homered in the fourth off Volstad, who exited after the Cubs' sixth-inning rally. Volstad allowed three runs in six innings to record his second consecutive quality start but, despite Volstad's recent improvement, the right-hander still hasn't recorded a victory since July 10, 2011 -- a span of 22 starts.
"Balls were hit hard early off him, and he kind of settled down and made a lot of good pitches and did a good job," Sveum said.
For Soriano, it's been a nice 12 full seasons in the Majors. The only year he failed to hit 20 homers was in 2001, when he hit 18 for the Yankees. He's gone through many changes throughout his career, from promising shortstop prospect to All-Star second baseman to a 40-homer, 40-stolen base left fielder in 2006 -- one of only four players in baseball history to accomplish the feat.
Although his best years are certainly behind him and some days his knees leave him vulnerable in the outfield, Sveum has continued to contend that Soriano is a player out of whom he knows what he's going to get.
"Those kind of guys, they've hit," Sveum said. "They've always hit; that's what they were born to do."
Soriano has continued to hit, and hit balls far, just as he did Thursday while proving himself as one of his era's most consistent power hitters.