Matusz tossed a four-hitter and struck out four in his return to Triple-A as the Norfolk Tides blanked the Charlotte Knights, 4-0.
After Ray Olmedo reached on a throwing error by third baseman Bill Hall with two outs in the second inning, the 25-year-old left-hander set down 11 straight batters. The streak ended when Drew Garcia singled with one out in the sixth, but Matusz (1-0) faced the minimum the rest of the way.
"I established my fastball early. I was able to get ahead early," said Matusz, who walked one and threw 81 of 114 pitches for strikes. "I made a nice adjustment on my changeup, I was using it effectively on righties, and later on in the game I was able to drop the curveball in for strikes."
The Tides defense, which Matusz credited, provided a late boost, turning double plays in the final two frames.
The Orioles assigned the 2008 first-round Draft pick to the International League following a stretch in which he surrendered 22 runs on 40 hits and 13 walks over 21 1/3 innings in five starts. Overall, Matusz was 5-10 with a 5.42 ERA in 16 starts for Baltimore.
"I've had my ups and downs," he said. "I've had my good starts and I've had some tough outings. There have been some games where it's been some bad pitches that have led to disappointing outings. For me, I didn't feel like it's a huge adjustment I need to make. I feel like I'm one good outing from getting on track. It's a matter of being consistent and getting a little confidence back.
"Anytime you get up there and have a good outing, it's a confidence-booster. It's nice to have a good outing like this, but it's important to follow it up with another good outing."
Establishing the fastball, like he did against Charlotte, is something Matusz hopes to continue to do.
"[Orioles manager] Buck Showalter made the comment that he wanted me to be able to establish the fastball, and I was able to do that tonight," he said. "Everything for me works off the fastball, it really helps me get in a nice groove."
The University of San Diego product made nine starts for the Tides last season. In his final outing on Aug. 11, Matusz tossed a five-hit shutout against Lehigh Valley. Two of his three complete games have come while pitching in the International League.
L.J. Hoes, the Orioles' No. 12 prospect, went 3-for-5 with a double and an RBI to raise his average to .307 for the Tides. Major League veteran Lew Ford homered and drove in two runs, giving him 28 RBIs in 44 games.
Philip Humber (0-1) took the loss in a rehab start for the Knights, yielding two runs on five hits over four innings. Pedro Hernandez struck out seven and gave up two runs over the final five frames.