And on Sunday against the Houston Astros they were pleased to see his work finally pay off with his first win since May 24.
"He's a strong kid," Rangers manager Ron Washington said of Martinez. "He works every day and he wants to be better. You've got to understand the kid is just out of A ball trying to get big league hitters out. He'll figure it out."
Martinez (2-8), who was pitching on five extra days' rest, allowed five hits and two runs with a season-high six strikeouts.
"I'm definitely relieved," he said. "It's nice to get that win. It wasn't easy. I had to battle out there."
He spent half of last season in Class-A and pitched just two games in Double-A this season before being called up after injuries decimated the Rangers' rotation.
"He's up here to win ball games," Washington said. "If we didn't have a tremendous feeling about the kid he wouldn't be up here ... we believe in him. We're going to give him all the opportunity that we can to continue to improve."
The Rangers trailed by two early before scoring twice in both the fourth and fifth innings to take a 4-2 lead. The 393rd homer of Beltre's career came off Dallas Keuchel in the sixth inning and Choo also had a solo shot in the seventh to make it 6-2.
Keuchel (10-8) allowed six hits and tied a season-high with five runs in six innings.
"I wasn't very good the last three innings, and that was the game," Keuchel said.
Jose Altuve had two hits for his 49th multihit game this season in his return after missing Saturday's game with a sore neck.
Chris Carter made it 1-0 in the first when he grounded into a force play that scored Robbie Grossman and left Altuve out at second. Carter was initially ruled out on the play, but manager Bo Porter challenged the call and it was overturned.
Altuve was plunked with one out in the third inning and added to his American League lead when he swiped second for his 46th steal. Jason Castro's single sent him home to make it 2-0.
A sacrifice fly by Andrus scored Robertson to push the lead to 4-2.
Rangers: Rios left the game in the middle of the fourth inning after appearing to aggravate his sprained right ankle sliding into home in the top of the fourth inning. He had missed the previous two games because of the injury, but said after the game that he expects to play on Monday. ... Washington was encouraged by LHP Derek Holland's third rehabilitation start at Double-A Frisco on Saturday night. He struck out four in three scoreless innings. Holland, who hasn't played in the majors this season after left knee surgery, will start for Triple-A Round Rock on Thursday night.
Astros: Astros OF George Springer (quadriceps) said he felt OK on Sunday a day after taking batting practice and participating in drills on the field, but he isn't sure when he'll be able to come off the disabled list. "It's more frustrating than anything because I want to play and help," Springer said. "But ... I have to be smart about it."
Rangers: Colby Lewis starts against Tampa Bay's Drew Smyly in the opener of a four game series on Monday. Lewis has gone 2-2 with a 2.30 ERA in four starts since the All-Star break and threw a complete game shutout in his last start.
Astros: Brad Peacock opposes Minnesota left-hander Tommy Milone when the Astros start a three game series with the Twins. Peacock will make his second start since being recalled from Triple-A Oklahoma City. He struggled in his return to the majors, allowing eight runs in five innings of a 10-3 loss to Philadelphia.