Rangers 10, Astros 5: Nelson Cruz hit a grand slam and Adrian Beltre and David Murphy hit two-run homers as host Texas routed Houston in the opener of a three-game set.

Nick Tepesch (4-6) struck out a career-best nine in five-plus innings and Leonys Martin had two hits and an RBI as the Rangers improved to 6-1 against the Astros this season. Texas remained a half-game behind the first-place Oakland Athletics in the American League West.

Murphy hit a two-run homer in the first off Lucas Harrell (5-9) and Texas loaded the bases in the second on a single and two walks before Cruz sent a blast over the left-center field fence to make it 6-0.

Beltre’s homer off the left-field foul pole in the fourth increased the lead to nine and Martin singled in a run in the fifth. Houston struck for four runs in the sixth on Jason Castro’s single, Chris Carter’s two-run double and J.D. Martinez’s single.

Tepesch allowed four runs and seven hits to snap a streak of eight straight winless starts. Harrell gave up nine runs (seven earned) and five hits while issuing six walks in 3 2/3 innings.

GAME NOTEBOOK: Cruz has hit six grand slams, one off the Texas record shared by Juan Gonzalez and Rafael Palmeiro. … Castro had three hits after entering the contest with five hits in 41 at-bats against the Rangers. … Martin has at least one hit in 17 of his last 18 games.