Wood (3-3) won his third straight start, and he has given up one earned run over his last 20 2/3 innings. He retired the first 12 batters he faced before J.D. Martinez doubled to lead off the fifth. All-Star Jose Altuve singled with two outs in the sixth, and Wood was charged with a hit when Brian Bixler reached with one out in the eighth, but Darwin Barney's throw to Rizzo appeared to beat Bixler by a half-step.
"I feel like he was mixing," Martinez said of Wood. "He had that cutter working. It felt like every time you were swinging, it was off the hands. He would throw that two-seamer and kind of just running it and cutting it. It was tough."
Wood tipped his cap to the crowd of 37,389 at Wrigley Field when he was pulled in the eighth. The turning point for the lefty may have been not making the Cubs out of Spring Training. He was sent to Triple-A Iowa and worked on his game there.
"I got my chance to come back up and I didn't want to waste it," he said.
The Cubs traded one of the best relievers in the game in Sean Marshall to the Reds as part of the package to get Wood.
"I knew it was somewhere in there," Sveum said. "He's made adjustments, and the confidence level he has is off the charts."
Wood extended his scoreless-innings streak to 18 2/3 innings, the longest by a Cubs left-hander since Ted Lilly had a 19-inning stretch from Sept. 10-20, 2008.
Wandy Rodriguez (6-6) was nearly as stingy. The Astros lefty retired the first seven batters before Luis Valbuena singled in the third. Barney singled with two outs in the fifth and Valbuena nearly had an extra-base hit, but center fielder Brian Bogusevic tracked the ball down in right-center.
The Cubs are now 6-17 against left-handed starters, and they have picked up three of those wins since the addition of Rizzo, called up last Tuesday from Triple-A Iowa.
"For whatever reason, we haven't done much against left-handed pitching, and that's been the biggest hole in our offense, which should've been a strength going into the season," Sveum said.
Wood helped himself when he doubled to lead off the sixth, and he moved up on Reed Johnson's groundout, waiting long enough for third baseman Matt Downs to throw to first before advancing.
"I love hitting and being on the bases," Wood said. "Since it's part of the game, I feel I try to be as good as I can. You're just helping yourself out there."
Sveum wasn't going to take the bat out of his pitcher's hands.
"His athleticism changed the game around," Sveum said.
"I made one mistake to the pitcher [Wood]," Rodriguez said.
All-Star Starlin Castro was intentionally walked, and Rizzo smacked the first pitch to right to drive in Wood. Jeff Baker followed with a two-run double to make it 3-0.
"From what I've seen so far, I'll take my chances with Rizzo at the plate and the hole open, too," Sveum said. "He's been here five days and he has three game-winning hits. You don't keep that stat anymore, but he's put us ahead three times and we've stayed in the lead in three of the five games."
The move to walk Castro made sense to Rizzo.
"I was just trying to get a pitch over the plate and it was a first-pitch curveball, and I didn't try to do too much with it," Rizzo said.
It's been a nice welcoming homestand for the 22-year-old first baseman.
"Five wins -- five out of six," Rizzo said. "It definitely feels good."