The Astros (21-23) are just two games under .500 and sit third in the National League Central standings, four games back of the first-place Cardinals.
"When you're winning, everything is great," right fielder Carlos Lee said. "You play loose, you take the lead, and you feel like later in the game with the way our bullpen is pitching, that we're going to win the game."
Rodriguez gave up eight hits and hit two batters in seven innings of work, but was able to strand a runner in scoring position in the third, fourth, fifth and sixth innings. He struck out five and didn't walk a batter.
The lefty knew that he didn't have his best stuff.
"I didn't feel very good with my fastball today," Rodriguez said. "You see in my game, I used a lot of my breaking ball because I didn't have a good [fastball] tonight."
Rodriguez (4-4) got enough run support in the first seven innings to pick up the win. Three of the Astros' runs came off hits from Martinez.
In the fourth inning with two out, Martinez flared a Jeff Samardzija pitch high in the air to right. Cubs right fielder David DeJesus appeared to have the ball in his glove before second baseman Darwin Barney plowed into him and knocked it free. The ball squirted into foul territory, giving Johnson time to score from first.
"I saw the right fielder running and I was like, 'It's going to have a chance. He's going to have to make a nice play on it,'" Martinez said. "I just continued to run right out of the box and was just fortunate it fell."
Martinez also had an RBI single in the Astros' three-run eighth inning. He went through a 1-for-33 stretch from April 28 to May 13 and now has eight hits in his last eight games.
"It takes some time for that to come back and I think that's probably where he is," Mills said. "It's just now it's coming back and he's starting to square some balls up again."
Martinez said he felt as comfortable at the plate Wednesday as he did during his slump.
"I just wasn't missing pitches tonight," Martinez said. "In the past, I felt like I was fouling those pitches off and I just wasn't doing that tonight."
Other than Martinez's triple, Samardzija (4-3) was able to contain the Astros' bats for most of his six innings.
"That was a pretty good battle," Mills said. "Samardzija was throwing the ball extremely well. We were having problems having good swings off him and we were able to get a break and score a couple of runs. That was big and it was sure nice to see."
The Astros also scored runs in the eighth on a bases-loaded walk by Matt Downs and after Cubs reliever Rafael Dolis plunked Jose Altuve with the bases still loaded.
Brandon Lyon and Brett Myers came out of the bullpen and pitched scoreless innings to hold onto the lead. Lyon's scoreless streak stands at 9 1/3 innings. Myers has made nine consecutive scoreless appearances at Minute Maid Park.
The Astros' starters made it through five innings for the 37th time in a row, now tied for the longest streak in the Majors after the Padres' 37-game streak ended on Wednesday.
"These guys have done a great job of making some adjustments to see what works, what doesn't work and make adjustments from start to start," Mills said. "I think they have confidence that they don't have to be real perfect, that they can still make some pitches. That's huge to be able to do that because the guys coming behind them are doing so well."
Lee, who had three singles on Wednesday, said the batters know that the pitchers have been a big reason for their recent success. The Astros finished 6-2 on the homestand.
"The starters throwing six, seven innings and the bullpen, they're incredible," Lee said.