Athletics 1, Rangers 0: Bartolo Colon tossed eight stellar innings and Brandon Moss provided the only offense with an RBI double in the first as visiting Oakland strengthened its lead atop the American League West.

Josh Donaldson scored on Moss' double and led off the sixth inning with a single to extend his career-best hitting streak to 10 games. Grant Balfour retired the side in the ninth for his 38th save as the Athletics posted their 15th win in 19 outings to increase their lead to 5 1/2 games over second-place Texas.

Ian Kinsler and A.J. Pierzynski collected two hits apiece for the reeling Rangers, who have lost five straight and 10 of 12. Yu Darvish (12-9) struck out 10 but dropped his fourth straight start while running his winless stretch to six games.

Colon (16-6) improved to 20-8 in his career against Texas after scattering seven hits and striking out as many. The 40-year-old Dominican yielded a one-out single to Elvis Andrus in the eighth inning and stranded him at third after inducing Adrian Beltre to fly out to the warning track.

After the teams combined for 17 runs in the series opener, Oakland needed just one on Saturday. Moss ripped a first-pitch cutter from Darvish down the first-base line to plate Donaldson, who deftly dove around the tag of Geovany Soto.

GAME NOTEBOOK: Colon is the only pitcher in major-league history to have defeated the Rangers 20 times. ... Darvish, who allowed one run on four hits, fell to 0-4 this season against Oakland and 1-6 in his career. ... Athletics DH Yoenis Cespedes went 0-for-4 with a pair of strikeouts to see his eight-game hitting streak come to an end.