The Rangers (8-10) brought out closer Eric Gagne in the ninth, but he faced only one batter before leaving the field with a limp. Akinori Otsuka replaced Gagne and walked Mark Ellis. Shannon Stewart singled to left field to put two runners aboard, but Nick Swisher struck out and Eric Chavez flied out to end the threat and the game.
The Rangers took an early 1-0 lead in the second inning off Chad Gaudin, who started on the mound for Oakland. Blalock tripled before Ian Kinsler brought him home on an RBI single. Nelson Cruz then doubled, but Gaudin and the A's (9-9) were able to escape the inning when Gerald Laird popped into a double play.
Gaudin really calmed down after that, and he retired 12 of the next 14 batters, surrendering only two walks along the way.
"Early on, I was struggling with my command a little bit," Gaudin said. "But I settled down and started getting ahead of hitters, and that makes it a lot easier to pitch."
Gaudin lowered his season ERA to 1.85 with the one run allowed, and he set a career high with seven strikeouts.
The A's offense evened the game in the fourth inning. Mike Piazza, who sat out Saturday night's game, doubled to center field to bring home Chavez. Piazza finished the afternoon 2-of-4 with the one RBI.
One inning later, Stewart broke the tie with a rifling two-run homer that just cleared the left-field wall. It was Stewart's second home run of the season, and it put Oakland up, 3-1. He finished the day with a pair of hits and a pair of RBIs.
The Rangers didn't manage much of a threat until the game-changing eighth. The frame began with a Lofton single. Frank Catalanotto then doubled to right, and Mark Teixeira drew a walk to juice the bases and set up the dramatic Texas comeback.
Duchscherer (1-1) was saddled with the loss. He faced six batters and allowed three earned runs on two hits with two walks in just two-thirds of an inning. Street was charged with a blown save, his first of the year.
Following the game, A's manager Bob Geren wasn't critical of his bullpen.
"It was a good game until late," Geren said. "Duke [Duchscherer] is usually very consistent. It's uncharacteristic for him to walk anybody. He made some real close pitches. He just missed. He wasn't that bad.
"I thought Huston did a very nice job," he continued. "It was a nice changeup. He got Blalock with one hand, off the end of the bat. It just happened to fall in there, so that was kind of tough luck right there."
Geren also was quick to praise the efforts of his starting pitcher on Sunday.
"Gaudin pitched good, so I'm happy about that," the A's skipper said. "That's the good news."
The bad news that followed was that outfielder Milton Bradley left the game with a hamstring injury. Geren said it was safe to assume that Bradley would not be available for Monday's contest, but he still didn't know if the injury would land Bradley on the disabled list. Bradley appeared to injure the leg running to first base on a single in the sixth inning.