Didn't need any help this time.
Wood beat Cincinnati for the first time in his career, repeatedly pitching out of threats for seven innings, and Chicago stalled the Reds' week-long surge with a 2-0 victory Monday night.
Wood (9-11) finally beat the team that traded him after the 2011 season. He was 0-4 in his career, including three losses this season, even though he had pitched well in most of the games. He allowed six hits and fanned seven.
Finally, he got them.
"It's the first time I've ever beaten them. That's really nice," Wood said. "I've pitched some good games against them, and they've gotten me a few times, too, so this one was nice."
Kevin Gregg gave up a double in the ninth while earning his 31st save in 35 chances.
The Reds were coming off a refreshing week -- six wins in seven games against the rival Cardinals and the NL West-leading Dodgers, leaving Cincinnati only 1 game out in the NL Central. And with St. Louis idle Monday, the Reds had a chance to gain a half-game on first place.
Cincinnati hasn't been within a game of first place since May 25. The Reds have won a lot of close games and made up a lot of ground since falling a season-high 7 games out on Aug. 8.
Facing a team they have dominated, they wasted a chance to move closer.
"We had a good run against the Cardinals and the Dodgers," Arroyo said. "It would have been nice to continue it tonight, but that's what good pitching does."
Cincinnati is 13-4 against the Cubs this season. Overall, Cincinnati has won 12 of its last 15 and 22 of its last 27 against Chicago.
The last-place Cubs started their longest trip since the 2004 season, 11 games in 11 days. They also go to Pittsburgh and Milwaukee.
Sweeney hit his sixth homer in the second inning and Valbuena hit his 11th in the third. Valbuena's homer left him 6 for 12 career against Arroyo with two homers -- one of the few Chicago hitters with good results against the right-hander.
Arroyo allowed seven hits over seven innings, striking out six.
Wood was traded to the Cubs for left-handed reliever Sean Marshall after the 2011 season. He had pitched well against the Reds, allowing only two runs in three of his four starts against them this season.
He didn't need much help this time.
"The luck he's had this year, it's just gratifying to see him get a win at any time," Cubs manager Dale Sveum said. "He's had some tough luck this year."
Wood forced Cincinnati to strand a runner at second base in the first, third, fourth, fifth and sixth innings. After Shin-Soo Choo doubled with one out in the fifth, Wood got Brandon Phillips and Joey Votto on called third strikes.
The Reds stranded seven runners in scoring position in seven innings.
"He's an All-Star," Reds manager Dusty Baker said. "He was able to make his pitches when he needed to. We had men in scoring position seven times in the game. We just couldn't get that hit tonight. "
Choo was hit in the back with a pitch in the third inning, the 25th time the leadoff hitter has been plunked this season. With that, Choo surpassed Jason LaRue for the club record.
It was the Cubs' sixth shutout this season. ... Reds SS Zack Cozart had two doubles, extending his hitting streak to a career-high 14 games. ... RHP Johnny Cueto continues to throw without pain. Cueto is on the DL for the third time this season with shoulder problems. The Reds haven't decided when he could pitch in a game or what role he might have. "You don't want to force him in there and end up hurting his shoulder," Baker said. "It's great to have him as a possibility." ... LHP Tony Cingrani (7-3) starts for the Reds on Tuesday, his second appearance since returning from back spasms. The Cubs go with Edwin Jackson (7-15), who leads the NL in losses.