Gio Gonzalez pitched six scoreless innings and picked up the win. (Mike Mcginnis/Getty Images)

This season has been trying for Washington Nationals starter Gio Gonzalez. His performance hasn’t been up to his usual standard or ability. He landed on the disabled list for the first time in his seven-year major league career, his inflamed left shoulder betraying him and forcing him to miss a month. Monday was only his second start back from injury, his season in need of mending.

Gonzalez climbed the mound at Miller Park on Monday to face the hot-hitting Milwaukee Brewers, the team with the best record in the National League, and he delivered six scoreless innings. They weren’t pretty, but Gonzalez battled his own command issues and waded through a right-handed-heavy, power-hitting lineup to send the Nationals to a 3-0 win in a showdown of first-place teams.

After he completed the sixth inning, Gonzalez received a huge smile and well-earned embrace from pitching coach Steve McCatty in the dugout. The Nationals’ gregarious left-hander hasn’t had much to be happy about this season, which so far has consisted of some clunkers, an injury and a dugout blowup. But Monday, he labored hard to send the Nationals to the win.

“It’s a huge accomplishment coming back especially with a team like that,” Gonzalez said. “The Brewers are red hot and I wanted to make a statement with the rotation and trying to be a part of it.”

First baseman Adam LaRoche provided the only offense of the game, a towering three-run shot to center field in the third inning, another notch on his potentially all-star worthy season résumé. The Nationals won even without Manager Matt Williams, who was ejected in the second inning for the first time as Washington’s skipper and watched the rest of the game from the visitor’s clubhouse.

The three-game series between the teams was billed as a showdown between one of the best pitching staffs in baseball and one of the best hitting lineups. By some measures, the Nationals have the best set of arms in baseball while the Brewers entered the series averaging more than 4.5 runs per game. Gonzalez entered with a 4.85 ERA and his confidence hurting, but pitched his best game in a month and a half.

“He’s happy but he’s not the happy-go-lucky Gio when everything is feeling great,” LaRoche said. “You can tell it’s been bothering him even before he went on the DL. Something wasn’t quite right. A nice break for him to be able to heal up and come back and the more starts he gets the more he’s going to get that feel back and confidence back.”

Gonzalez ran into his biggest jam in the third inning. He battled Brewers catcher Jonathan Lucroy, the team’s best hitter this season, for 11 pitches but walked him on an inside fastball to load the bases with two outs. Shortstop Ian Desmond and McCatty paid Gonzalez visits to the mound.

Gonzalez threw two change-ups to Brewers slugger Carlos Gomez and the cleanup hitter lifted the second one to left field for a flyout. Gonzalez escaped the inning unscathed.

“Not giving back those runs was a big boost for all of us,” he said.

Gonzalez tossed three more innings, working around a walk in the fourth inning and a double in the fifth. He relied heavily on his change-up to get out of jams.

After issuing a walk in the sixth inning, Gonzalez got Khris Davis to ground into a double play to end the frame. Gonzalez walked off the mound after his six innings of work. He walked four batters and threw 68 strikes out of 114 pitches.

“I think this one might carry him over the hump a little bit and give him some confidence and it really helps our staff,” bench coach Randy Knorr said.

Williams watched Gonzalez’s uplifting performance from the clubhouse after his ejection in the second inning.

The Nationals had bases loaded with no outs against Brewers starter Matt Garza in the top of the inning but didn’t score. Danny Espinosa struck out looking, Jose Lobaton struck out swinging and Gonzalez grounded out. But what likely irked Williams was a called third strike to Espinosa.

The pitch, the sixth of the at-bat, appeared to be just outside the strike zone on replays and Williams didn’t like it. He chirped at umpire Mark Wegner from the dugout and was tossed within seconds. He then emerged fuming from the dugout but it did no good. Williams retreated to the clubhouse and Knorr managed the rest of the game.

“I was having a discussion and so he decided that he didn’t want to hear it,” Williams said. “It bothered me that my hat was a little tight [Monday night],” he added with a smile. “He didn’t want to talk to me anymore.”

For all the inconsistencies and injuries in the Nationals’ lineup, LaRoche has been the steadiest force of all. Despite missing two weeks with a quad strain in late May, the left-handed power hitter has barely skipped a beat. Monday’s home run was his ninth of the season, and six have come with men on base.

“The more pitches you see you get your timing down a little more and more,” LaRoche said. “And he left a slider out over the plate. In that spot, you’re really trying to hit something hard and hit something in the air.”

While LaRoche provided the offense, the Nationals’ bullpen — Aaron Barrett, Drew Storen and Tyler Clippard — completed Gonzalez’s start. The Nationals walked off the field happy, and no one perhaps more than Gonzalez, who showed signs of getting his season back on track.

“It was just one of those nights I needed to bounce back,” he said.