The Rangers expanded their lead in the seventh on a solo shot by Beltre, his eighth homer of the season.
Neftali Feliz limited Houston to a run on four hits, but he walked six and was relieved by Robbie Ross with two on and two out in the fifth.
Ross (5-0) ended the threat by getting Brian Bogusevic to ground into a fielder's choice and then worked two more innings to collect the victory.
Joe Nathan struck out one during a perfect ninth for his ninth save.
Wandy Rodriguez (3-4) was charged with the loss. He gave up all four runs on 10 hits over six-plus innings. Houston had won two straight.