The Rangers failed to reduce their magic number below 6 on Sunday, losing at Seattle, 2-1.
Meanwhile, the Oakland A's beat the Minnesota Twins, 6-2, to keep their slim hopes of catching the Rangers in the AL West from becoming even slimmer. The A's trail by nine games.
The only offense for the Rangers came on a sixth-inning solo home run by Nelson Cruz. It came on the heels of Vladimir Guerrero getting thrown out at second after hitting a ball off the left-field wall.
The Mariners bounced back with the tying run in the bottom of the sixth and the go-ahead run in the seventh.
The Mariners won the series, 2-1, but the Rangers have dominated Seattle this season, 11-5. The AL West rivals play one more time this season, a three-game series in Arlington on Sept. 27-29.
The Rangers only scored one run despite rapping out 10 hits.
Rangers starter Tommy Hunter (12-4) allowed two runs on six hits in six-plus innings but was unable to pick up his 13th win of the season.
Right-handed reliever Clay Rapada pitched a scoreless inning in relief and has now gone five innings without allowing a hit or a run since the Rangers called him up earlier this month.