Gallardo struck out a career-high 14 in seven innings and the Brewers used a four-run sixth to beat the Pittsburgh Pirates 4-1 on Sunday.
"It's really like win or go home every game," Gallardo said. "We all know the nine games we have here, the next series with the Cardinals, then the Reds. They're very important."
Gallardo (8-6) gave up four hits, including Andrew McCutchen's homer in the fourth.
Milwaukee took two of three from the Pirates. St. Louis comes in for three and then the homestand ends with three against the Reds.
Gallardo struck out two in every inning except the sixth when he fanned just one and the side in the seventh.
"Command was probably the best I've had all year," he said. "That really helped."
Pirates manager Clint Hurdle felt that the team took itself out of the game against Gallardo.
"We got in a bad rut here, swinging the bat as far as striking out," Hurdle said. "Gallardo was very good today. We were susceptible to a lot of things he was doing. He had a very sharp breaking ball."
Gallardo won consecutive starts for the second time this season.
Martin Maldonado went 3 for 4 with one RBI for Milwaukee.
John Axford pitched the ninth for his 16th save.
McCutchen, who had three of the Pirates' five hits, hit his 21st homer and fifth in the past four games. He also had two singles. He is batting .560 (28 for 50) with seven homers, 19 runs scored and 16 RBIs in past 12 games and leads the majors with a .371 average.
"He is as good a player as there is in the league," Hurdle said. "He is playing at an elite level, all across the board. He has earned his name being in those (MVP) conversations at this point. But it is still early. We've all got work to do."
McCutchen made an impression on Gallardo, too.
"He's on fire," Gallardo said. "He's swinging the bat very well. That home run was a pretty good pitch. It was on the outside part of the plate."
A.J. Burnett (10-3) had his career-high nine-game winning streak ended.
"Things happen. It's baseball," he said. "It's not from a lack of effort. These guys try as hard as they can out there. It just didn't go our way."
It did go the Pirates' way early as Burnett stranded seven runners in scoring position through five innings, but then Milwaukee pushed across four runs and four hits and one error in the sixth.
Nyjer Morgan singled. Ryan Braun singled to right fielder Garrett Jones, whose throw sailed passed the cutoff man and allowed Morgan to score. Braun went to third on the play and scored on Aramis Ramirez's RBI single.
Ramirez stole second as Corey Hart struck out. Ramirez scored on Rickie Weeks' double, who then scored on Maldonado's third hit of the game.
"We didn't defend very well behind him (Burnett) which complicated it," Hurdle said. "The throw and the play at third, those are plays we got to make. We didn't handle the inning very well. A.J. pitched a very, very good ball game today."
Burnett allowed four runs and nine hits and struck out seven in seven innings.
NOTES: The last Pittsburgh pitcher to win more than nine straight decisions was Dock Ellis with 13 in 1971. ... Walker extended his hitting streak to 15 games with a single in the first. ... Jeff Bianchi made his Brewers' debut in the field when he started at shortstop. His contract was selected from Triple-A Nashville on Thursday. He pinch hit on Friday and struck out.