He gave up just two runs on five hits in seven innings of work.
Mikolas, like most of the young Rangers pitchers, has struggled with consistency. On July 27 against Oakland, Mikolas lasted just 4 2/3 innings in allowing eight runs (seven earned) and four walks in a 9-3 loss.
Saturday night, he found his curveball and was consistent in throwing strikes with his fastball.
"He was changing speeds," manager Ron Washington told reporters of Mikolas. "He was hitting his spots and he made a lot of good pitches in some situations where he had to."
The hitters failed Mikolas. The two biggest threats came in the sixth and ninth innings.
In the sixth, with two runners on, Adrian Beltre bounced into a groundout at first but Elvis Andrus was tagged out in a rundown on J.P. Arencibia's fielders choice, Leonys Martin struck out to end the inning.
"We just couldn't get any base hits in (key) situations," Washington said. "We created some opportunities and we just didn't deliver. That's just been our issue on the offensive side."
Notes: The Rangers have not named a starter for Wednesday's game at Chicago. Nick Tepesch, who threw a bullpen session on Friday in Cleveland, is tentatively scheduled to do it. ... C Geovany Soto went 1-for-3 with a 2B for Double-A Frisco on Saturday night in his second rehab start. ... LHP Derek Holland will pitch Game 1 of a double header at Triple-A Round Rock on Monday in his second rehab start.