Rangers pitchers combined to allow three hits and two walks while striking out nine. Ramos, in his third start, earned his first win of the season despite a fastball that never got over 88 mph.
"He pitches his tail off every time," closer Sam Dyson said. "Four quality pitches around the zone. It was nice to go out there and see him give us a good outing."
Dyson was the third of the Rangers' three relievers on the night, all of them throwing 96-97 mph. Matt Bush pitched a scoreless seventh despite allowing a two-out walk and a single, and Jake Diekman struck out two while retiring the side in order in the eighth.
That left the ninth to Dyson, and the newly named closer also went 1-2-3 with two grounders back to the mound and a game-ending strikeout of Carlos Correa.
"I feel like all our guys came out of the bullpen throwing strikes, pounding the strike zone and staying efficient with all their pitches," manager Jeff Banister said.
Bush was making just his fourth appearance since being called up to the Major Leagues, but the 30-year-old rookie is showing the Rangers he can handle the late-inning pressure. He has allowed just three baserunners in four outings and has yet to allow a run.
"He hasn't shown us another look but unfazed," Banister said. "I believe Matt is going to stay poised and composed. He waited a long time to get here and faced adversity most of us have never seen. Being out in a game is his most comfortable situation."
Ramos' outing was from the left side and followed the same plan as the one delivered by right-hander Colby Lewis on Friday night. Lewis pitched seven scoreless innings, while Ramos allowed only a solo home run by Marwin Gonzalez.
"Very similar to what Colby did," Banister said. "He had nice fastball, curveball, slider combination, a few changeups, the ability to throw strikes early in the count, an efficient, quick outing."
Added Astros manager A.J. Hinch said, "Ramos mixed and matched and threw different speeds and different pitches and never really doubled up on anything the entire night. It was too much for us tonight, apparently."
Ramos faced 19 batters and only three reached base -- on the home run, a single and a walk.
"I just tried to take advantage of their aggressiveness," Ramos said. "From the first inning, they told me they weren't up there to take pitches. They were up there to swing as hard as they could. I just tried to keep them off balance and guessing."
Ramos' first pitch of the game was 86 mph. Dyson's last pitch was 96. The Rangers did it both ways on Saturday.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.