TUCSON, Ariz. -- Randy Johnson was happy to pitch without pain. Still, he was disappointed with the results of his first outing since back surgery.
The Big Unit gave up three runs and four hits, including a three-run homer by Chris Iannetta, in 1 1/3 innings Monday during Arizona's 10-9 victory over the NL champion Colorado Rockies. Johnson walked one and struck out one.
"Minus the results today, there was a lot of positive things," he said. "But as competitive as I am, I'm still disappointed that I would pitch like that."
The 44-year-old left-hander returned to the mound for the first time since June 28. Last summer, he underwent back surgery for the second time in less than a year, but Monday he said he felt healthy.
"I've got a long ways to go, but I'm just happy to be able to get out there and pitch pain-free," Johnson said. "Comparing today to the last time I pitched at Chase [Field], it's night and day. So I'm happy about that. The results will come as I pitch more."
In the first, Johnson gave up a one-out double to Troy Tulowitzki, then got Todd Helton to foul out to the catcher and struck out Matt Holliday to end the inning.
Trouble came quickly in the second, when Garrett Atkins and Brad Hawpe opened with sharp singles. Johnson fell behind 3-0 to Iannetta, who hit a long homer to left.
"It's nice to know your swing is doing pretty good," Iannetta said. "Then again, Randy is just out there getting his work in. He's going to be a different pitcher during the season."
Johnson then walked Jayson Nix before Cory Sullivan flied out. That's when manager Bob Melvin lifted Johnson, who threw 33 pitches, 20 for strikes. The five-time Cy Young Award winner left to a standing ovation from fans behind the visitors' dugout at Hi Corbett Field.
"I'm not looking too much at results," Johnson said. "I'm looking to gain some endurance and stamina and work on my location and all those other little things on top of monitoring my back at the same time."
Johnson said he wasn't sure what to expect when he took the mound on a sunny, 67-degree afternoon.
"I was actually kind of nervous," he said. "Today, anything could have happened. I could have thrown a pitch and it could have been over. It wasn't. The point being is that I didn't know what to expect. I put a lot of hard work into it, but I can see that I still have a long ways to go to get my innings under my belt and to get where I need to be."
Johnson expects to make his next scheduled start, against the Los Angeles Angels on Saturday in Tempe.
"All in all, I thought it was a good first outing," Melvin said. "He just got a little bit fatigued in the second inning. The guy hasn't pitched since June."
Melvin wouldn't speculate on whether Johnson might be ready to open the season with the big league team.
"I'm not going to rule anything out," Melvin said. "If you look at where he is compared to some of the other starters right now, it might be a stretch. I'm just not going to commit to anything along those lines yet."
The Diamondbacks hope a pain-free start is a sign that Johnson can make a big contribution as they defend their NL West title.
"Hopefully, he comes back healthy and can start 33, 34 starts," Brandon Webb said. "Is he going to be able to do that? We don't know and I don't think he knows yet, so we're going to have to wait and see. He's going to be key for us if we can get him healthy and in the rotation for most of the season."
Nix also homered for Colorado, and Atkins was 3-for-3. Rockies starter Josh Towers gave up four runs and five hits in four innings.
Stephen Drew and Chris Burke homered for the Diamondbacks.