Mazzaro (3-2) was subbing for left-hander Dallas Braden, who was scratched from his scheduled start because of tightness in his pitching elbow. Mazzaro, who last pitched June 23 in a loss to Cincinnati, allowed one run, walked a career-high six and struck out two. Three of Mazzaro's seven career victories have come against the Orioles, who had a four-game winning streak snapped.
"Actually it was [Mazzaro's] day to pitch, so physically he was ready to go," said A's manager Bob Geren. "He battled. He really didn't throw as many strikes as the scoreboard would indicate. It was almost 50-50, balls and strikes. But I guess he threw enough strikes to make it work for him."
Geren had told Mazzaro -- whose turn was supposed to be taken by Braden, who got an extra day's rest after his last start -- when he reported to Camden Yards to be ready to go in the first inning if Braden ran into trouble. Mazzaro was the logical replacement once Braden was scratched.
Mazzaro threw 94 pitches, 48 of them for strikes, and kept extricating himself from jams caused by walks. He had only one 1-2-3 inning -- his last, the sixth -- and departed after walking Julio Lugo to open the seventh.
Baltimore helped Mazzaro out by stranding seven of the runners he allowed -- and 10 for the night.
"Six walks is a lot. It's tough to pitch around that, but I battled and got into some jams and stuck with the fastball and got the ground balls when I needed them," Mazzaro said. "It worked out pretty well.
The right-hander was also helped out by two key defensive plays -- a double play in the second when right fielder Rajai Davis gunned down Luke Scott at the plate, and Coco Crisp's running catch in the left-center gap to deny Corey Patterson an extra-base hit in the seventh.
"Our pitching has been doing a good job of keeping us in games and keeping us ahead when we are ahead," said Crisp, who was 3-for-4 with two stolen bases and two runs scored. "For us, it's going to take a collective effort offensively to win games. That's what we've been able to do recently."
Even the offense the A's were able to muster against hard-luck loser Brian Matusz was hardly earth-shattering.
Suzuki drove in runs in the third and fifth innings to stake the A's to a 2-0 lead. In the second, Cliff Pennington led off with a single, went to second on Crisp's single to left, advanced to third as part of a double steal and scored on Suzuki's two-out infield single to third.
Crisp led off the fifth with a triple to right field off Matusz (2-9) and came home when Suzuki grounded out and first baseman Ty Wigginton bobbled a possible double-play ball before throwing to Matusz covering at first.
The Orioles finally got to Mazzaro in the fifth, an inning that saw both benches warned after Baltimore leadoff hitter Lugo was hit in the back. Lugo jawed at Mazzaro as Suzuki and home-plate umpire Fieldin Culbreth ushered him to first base, and several Orioles spilled out of the dugout. Culbreth restored order and issued warnings to both benches, figuring Lugo's plunking was retaliation for Daric Barton being hit in the back in the top of the inning.
"I was just trying to go in. I had [Lugo] 1-1. I'm not trying to bag him, I'm trying to get him out," said Mazzaro. "Heat of the moment, he was a little upset, but whatever, it's done with."
After the game, Lugo was still steaming, claiming Mazzaro was a little too close to his head for comfort.
"I don't know if [Mazzaro] did it on purpose or not," Lugo said. "Like I said, I didn't like it -- he hit me too close to the head. It about hit me in the face. I didn't like that."
Mazzaro threw a wild pitch that the next batter, Cesar Izturis, claimed hit him in the foot, but Culbreth wouldn't allow him to take first base, insisting the ball had first struck the dirt. It worked out for the Orioles when Izturis followed with a run-scoring double to left.
Suzuki struck again in the seventh, when the A's chased Matusz. With one out Barton singled and Matusz was replaced by Jason Berken. Conor Jackson drew a walk and Suzuki chopped a grounder off the glove of third baseman Miguel Tejada for an RBI single and a 3-1 lead.
Matusz allowed three runs on seven hits over 6 1/3 innings, walking one and striking out two. He hasn't won in 13 starts since April 18 at Oakland.
The Orioles got within a run in the eighth when doubles by Nick Markakis and Scott off Craig Breslow made it 3-2. But Jackson's RBI single plated Crisp, who had led off the ninth with a double, for an insurance run and Andrew Bailey retired the side in order in the ninth for his 15th save in 18 tries.