The 24-year-old right-hander allowed three hits while striking out 10 over 8 1/3 innings. He threw 112 pitches -- 82 of them for strikes -- and did not walk a batter.
In four June starts, Martis is 3-1 with a 2.10 ERA while holding Eastern League hitters to a .172 batting average. He's fanned 61 and walked 18 in 61 innings this season.
"I've been working on my mechanics lately and trying to be more aggressive," Martis said. "Today, I mostly used my fastball and slider and didn't use the change-up as much. I was definitely trying to attack the strike zone."
Martis (5-3) got off to a strong start against the Curve, retiring the first 10 batters he faced before yielding a one-out double to Altoona second baseman Brock Holt in the fourth inning. Curve pinch-hitter Brad Chalk added a single in the sixth.
After striking out Quincy Latimore to open the ninth, Martis gave up his third hit, a double to Curve center fielder Starling Marte. Reliever Rafael Martin came on to complete the shutout with two quick flyouts.
"[Marte] fouled off a lot of pitches and I was already over 100, so I had to come out," Martis said.
The Curve had just three baserunners in the game, none of whom advanced past second base.
Harrisburg got on the board with four runs on four hits, an error and a wild pitch in the fourth inning. Catcher Devin Ivany and center fielder Jonathan Tucker singled in a run apiece in the frame.
Ivany added a two-run homer, his second of the year, in the eighth. The Senators went 2-for-6 with runners in scoring position.
Altoona starter Phillip Irwin fell to 1-1 in two Double-A starts since being promoted from Bradenton. He allowed four runs -- three earned -- on six hits over five frames. The right-hander struck out six and did not walk a batter, but did throw two wild pitches, one of which brought in a run.
The Senators outscored the Curve, 11-1, in the series.
Altoona, which fell to 5-11 against Harrisburg this season, has lost five straight games and eight of its last nine.