"Obviously, I set the bar way too high the first time," Kennedy said.
The loss snapped Arizona's five-game winning streak.
Kennedy (5-6) flew to Dallas early Tuesday after staying behind in Phoenix, but the added travel did not seem to have an effect early in the game.
Through five innings, Kennedy held the Rangers to just one run. That tally came in the first inning when with two outs, Kennedy uncorked a wild pitch that allowed Ian Kinsler to scamper home.
"In between the first and sixth inning, when we finally got him, he had a good changeup and he was using our aggressiveness to his advantage," Rangers manager Ron Washington said of Kennedy. "In the sixth inning, we started laying off the changeup and made him put it in the zone. When we did, we put some good swings on it."
While Kennedy was working to keep the Rangers from adding to their one-run lead, his mound opponent, Colby Lewis, was managing to keep the D-backs off the bases completely.
The Rangers right-hander had a perfect game through 5 1/3 innings, and over that span, the D-backs hit just one ball hard.
"We didn't make an adjustment to their pitcher," D-backs manager Kirk Gibson said. "Give him credit for throwing a very good game, but we were jumping at the ball and trying to pull him too much. He had all his pitches working, spotting his fastball, his slider, throwing a breaking ball and changeup, basically kept us off balance and we just didn't have a very good approach on him tonight."
Finally, with one out in the sixth, Aaron Hill laced a single to center on an 0-2 pitch to break up the no-hitter.
"If you don't know you haven't given up a hit, you're lying," Lewis said. "It was my fault, I hung a slider and he hit it. It's no big deal, you just go out and get the next guy. It's not like there is two outs in the ninth. It's still early and you have to still go out there and get outs."
Lewis continued to rack up the outs as he managed to go the distance for the second time this year.
The lone run against him came in the eighth when Miguel Montero hit a solo homer to center.
"He was able to get quick outs," Montero said. "He made good, quality pitches early and he got quick outs and he mixed his speed pretty well. You have to give credit to him, he pitched a heck of a game."
Kennedy seemed on his way to twirling a gem, as well, when he retired two of the Rangers' best hitters -- Josh Hamilton and Adrian Beltre -- to open the sixth.
Then the wheels came off.
Michael Young grounded a single to right and Kennedy missed his spot with a 2-1 changeup, and David Murphy made him pay by lofting the ball down the right-field line for a home run and a 3-0 Texas lead.
"Even when the game was 3-0, I thought we had a good chance to come back," Montero said.
Unfortunately for the D-backs, that was not where the game remained, as the Rangers went on to string together four straight hits off Kennedy to plate three more runs and grab a commanding 6-0 lead.
"Just a bad changeup, left it up," Kennedy said of the pitch to Murphy. "After that, I didn't make as quality of pitches as I was making earlier in the game, and when I did, they put the bat on the ball in the right place, in the right spots. Just bad pitches, leaving the ball up where they could hit it. It's frustrating when you can't get that third out."