The left-hander retired the first 13 hitters and 21 of 23 before allowing three consecutive singles to start the eighth.
He is the third Colorado pitcher in the past six days to make his major league debut. The Rockies optioned right-hander Chad Bettis to Triple A to make room for Matzek.
Matzek (1-0) allowed two runs on five hits and struck out seven in seven-plus innings. He also had his first hit and run scored. The Rockies had lost 11 of 12.
Julio Teheran (6-4) entered Wednesday with a 1.89 ERA, best in the majors, but Colorado scored three in the first on Drew Stubbs’ RBI double and Corey Dickerson’s two-run triple. Teheran allowed seven runs on 10 hits and struck out five in 6⅓ innings.
Troy Tulowitzki and Justin Morneau had three hits each for Colorado.
Matzek breezed through the first four innings on 39 pitches. Atlanta hit three balls hard, including a line drive by Teheran snared by Morneau to end the third.
Morneau couldn’t come down with Justin Upton’s single with one out in the fifth to give the Braves their first baserunner. The Coors Field crowd acknowledged Matzek’s early work with applause after Upton’s hit.
Upton was back in the lineup after being removed in the first inning Tuesday because of a left hamstring injury.
Chris Johnson followed with a single to right but Matzek retired the next two batters to get out of the inning.
Johnson, Tommy La Stella and Andrelton Simmons singled to start the eight and make it 8-1.
Franklin Morales came on and gave up a two-out RBI single to B.J. Upton before getting Freddie Freeman to fly out.
The Rockies made it 4-0 in the third when Tulowitzki scored on a sacrifice fly by Stubbs.
Josh Rutledge scored from third when Tulowitzki, who singled, was caught in a rundown between first and second in the fifth. Stubbs and Dickerson led off the sixth with consecutive doubles to give Colorado a 6-0 lead.
Tulowitzki and Morneau had RBI singles in the seventh.
Atlanta catcher Evan Gattis singled in the eighth to extend his hitting streak to 12 games.