The right-hander turned in his third straight solid outing as he pitched the D-backs past the Reds, 3-1, on Thursday afternoon in front of 22,090 at Great American Ball Park.
Lopez (6-14) allowed one run on eight hits over seven innings. Over his last three starts, he has a 2.79 ERA and has pitched into the seventh inning 13 times in his 30 starts this year.
"He was great," interim manager Kirk Gibson said. "He had a big smile on his face, I know that. It's been a long time coming. He's fought through a lot, he didn't really throw the ball well for a period of time. He really worked hard and made some adjustments, and he's really got it back."
Lopez has done a little less with weights in between starts and no longer throws a bullpen session, but rather just throws from flat ground.
"I guess he was working a little too hard, so he got a little fatigued," Arizona catcher Miguel Montero said. "So now he's working a little less, so he's more fresh for the games. He has more [velocity] on his fastball, better command. He's coming fresh every five days. He looks a lot better. He looks like he's got something behind the ball, it's getting there a little quicker, a little better, his breaking ball is sharper. His command is there right now."
The Reds took an early lead against him, though, when Drew Stubbs led off the bottom of the first with a single and, two outs later, came in to score on a double to center by Jonny Gomes.
But that was all the runs Lopez would allow as he used his good command to keep his pitches down in the zone, which is a must for him to be successful.
"It seems like the ball wasn't carrying like the first day we were here," Lopez said. "In the first inning, Gomes got it pretty good, but at least the ball stayed in the park. I just tried to keep the ball down."
Prior to his last three starts, Lopez had allowed 20 runs in his previous four outings and baserunners seemed to steal on him at will.
To combat the stolen bases, Lopez made a slight change in his mechanics.
"I think the big adjustment has been from the stretch," he said. "That helped me a lot to control the running game and to keep the ball down from the stretch. I think that's been the major adjustment that I've made the last few starts, and I guess it's paying off."
The win was his first since July 8, a span of 11 starts.
"I'm starting to feel more comfortable again on the mound," Lopez said. "I'm not battling with myself on the mound. I'm concentrating on keeping the ball down and just letting it go. I think that keeps me pretty focused during the game and more relaxed."
Cincinnati starter Edinson Volquez (3-3) easily handled the D-backs through the first four innings, holding them to just one hit while fanning four.
In the fifth, though, Volquez walked the first two hitters and the D-backs made him pay as both runners would eventually score during a three-run rally.
Gerardo Parra drove home the first run of the inning with a double and Stephen Drew and Kelly Johnson each added run-scoring singles as the D-backs jumped ahead, 3-1.
"That's always good," Gibson said of capitalizing on the walks. "We've been on the other end of that before. When you put the ball in play, you get people on and move people around."
Juan Gutierrez pitched the ninth to pick up his 10th save and give the D-backs a split of this four-game series.
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.