ARLINGTON -- The A's have handed out plenty heartbreak this season, but suddenly they're being forced to stomach some of it themselves, and in the most inopportune of times.Monday's 5-4 defeat to the Rangers, who got a walk-off single from Adrian Beltre in the ninth inning, marked the A's third loss in their last four games, all of which have culminated in an on-field celebration for their opponents. "A couple of breaks go our way, we could have won each of those games," Josh Donaldson said. Instead, the A's are now spread five games apart from the American League West-leading Rangers, whom they'll play in six of their final nine games, including three more in Texas this week. Moreover, their lead over the idle Angels in the Wild Card race slipped to two games, their distance from the Orioles, who hold the top spot, at 1 1/2. This following a stretch that saw the A's win 17 of 21. They've since dropped six of eight. "Wins are at a premium right now, and every day is just a battle," starter Dan Straily said. Straily did his part, handing the ball over to a beleaguered bullpen with a 4-2 lead intact, after allowing two runs (one earned) over 6 2/3 innings in his first career outing at Rangers Ballpark. The A's bullpen is quickly learning that there is no rest for the weary. Not now at least, when meaning is tied to every game. Oakland's relievers have worked overtime in recent days, their innings pitched totaling 36 2/3 over the past eight games, including 19 in the last four. Again, on this night, their club's fate rested in their hands. Again, they ultimately stumbled. Righty Tyson Ross, who loaded the bases in the ninth before surrendering the decisive hit to Beltre, couldn't solely be blamed. Two innings prior, with Straily's pitch count at 99 and Josh Hamilton, who had homered off him in the fifth, it was Jerry Blevins turn. And it was the lefty reliever who issued a two-out walk to Hamilton and righty specialist Pat Neshek who surrendered an ensuing game-tying, two-run homer to Beltre that prevented from tallying a much-deserved win. "He just made a bad pitch to Beltre," manager Bob Melvin said. "He's got him in a good count to potentially expand, and what he was trying to do was throw a slider off the plate, and he just left it on the plate." "We like our chances in that situation," the Rangers' Michael Young said. "Oakland has really great pitching but Adrian is swinging the bat as well as anybody in baseball right now." More times than not, Oakland's bullpen has been one of the best in the game, too. Its members are simply tired, it seems, leaving Melvin shorthanded, which factored into the decision to send the struggling Ross out for the ninth. Closer Grant Balfour was only to pitch if the club went ahead. "We just never got there," Melvin said. "It's one game. We gotta bounce back. We did that in both Detroit and New York, lost some tough ones and we bounced back and won the last game of each series. It would have been nice, obviously, start off with a win in this series, but if you can't, you gotta move on from it." Owners of 14 walk-off victories, the A's are growing tired of watching their opponents enjoy them. And it seems it could be avoided, given a better defensive display in the early innings. Straily could've seemingly stayed on the mound longer had two miscues produced from his defense, one each from Donaldson and Chris Carter, not upped his pitch count. "That's not like us," Donaldson said. "We can't give these guys free outs. They're too good." "We weren't very good defensively early on, and it probably cost [Straily] some pitches and at least one run," Melvin said. "Still, you have to move forward and you have to remain positive you'll win and we still had that opportunity, and we just didn't make the pitches at the end we needed to." The A's offense couldn't do much of their own in the later hours, their last run coming in the sixth, via an RBI base hit from Cliff Pennington. It was Josh Donaldson who got the A's on the board first with a two-run homer in the second off lefty Derek Holland and Yoenis Cespedes who also tagged Holland for a homer -- his 21st of the season -- in the third. But the biggest hit didn't even need to leave the ballpark. "If I don't give up a few runs, then it's a different story in the game, so it's not on any one person," Straily insisted. "It's definitely a team effort."