The seven-run barrage was the Padres' second in three games, having scored as many on Sunday against another rookie, the Mets' Matt Harvey. Quentin homered in that game as well.
"We're getting a little bit more offensively," manager Bud Black said.
Black spoke of the difference a hitter like Quentin, a two-time All-Star, can make in a lineup.
"He's dangerous every time he steps in the box," Black said. "He's a proven offensive player when he's in there. He's a weapon, an offensive weapon."
The Padres pushed four runs across in the third, when the first five batters reached base. Ohlendorf led off the attack with his first hit for San Diego, and Headley's single up the middle with the bases-loaded plated a pair. Everth Cabrera singled home two more runs later in the frame.
"Pitching is the most important thing, but it was nice to get a hit there," Ohlendorf said. "I ended up starting a big inning."
Quentin smacked a 2-1 pitch from Raley over the fence in left to extend the lead to 7-0 in the next inning. The home run, Quentin's 12th, is his fourth against the Cubs this season. The 29-year-old slugger debuted for San Diego at Wrigley Field in May and had three homers in the series and is 9-for-18 against Chicago this year.
Ohlendorf (4-2) allowed two runs (one earned) on three hits and snapped his two-game losing streak. He struck out three and walked one, and said the hefty run support helped his effectiveness.
"It has been a lot of fun with what we've been doing lately," Ohlendorf said. "When you know the team is going to score some runs, you don't worry as much about things like a solo homer so much.
Chicago rallied in the seventh after chasing Ohlendorf from the game. Brad Boxberger entered when Bryan LaHair's drive to right field bounced off the glove of Chris Denorfia. Steve Clevenger and Josh Vitters followed with run-scoring hits to pull the Cubs within 7-4 against Boxberger, who recorded only one out.
Alex Hinshaw came in and walked the first batter he faced before striking out Brett Jackson. Brad Brach entered the game and struck out Starlin Castro to end the threat.
"I thought [Ohlendorf], in the seventh, just ran out of gas," Black said. "He had a nice mix of his pitches and the secondaries were outstanding."
Luke Gregerson retired the side in the eighth, and Huston Street converted his 20th save in as many chances, extending a collective run of dominance for the two relievers, who have combined to throw 35 2/3 consecutive scoreless innings.
The All-Star Street continued his own run of eight straight seasons with 20 or more saves, earning praise from Black not long after the club signed Street to a two-year contract extension.
"[Street] has been extremely consistent," Black said. "I think he has really embraced being a Padre, as evident by the extension. He's in a good spot right now. Physically, he's good and mentally he's good."