A four-hit, two-out rally in the ninth inning fell just short for the Rangers, as Adrian Beltre struck out with two runners aboard to stymie a comeback win.
Rookie left-hander Martin Perez's streak of consecutive starts with a win ended at six as the Rangers fell to the Pirates, 5-4.
Entering the bottom of the ninth inning trailing 5-2, David Murphy and Mitch Moreland struck out to start the Rangers' final frame.
But a two-out rally started with an infield hit by Leonys Martin, and continued with singles from Ian Kinsler, Elvis Andrus, and Alex Rios that brought home two runs and put Beltre up with runners on the corners and a one-run deficit.
But the rest is history.
Andrew McCutchen was responsible for four of the Pirates' five runs, scoring one and driving in three. The three RBI included what would be the decisive run on a single off of Joakim Soria in the top of the ninth inning.
McCutchen also started the scoring for Pittsburgh.
He hit a sharp ground ball off of Perez in the third inning that scored Tony Sanchez from third allegedly.
Replays showed that Sanchez's foot never touched home. The Pirates' catcher stepped on A.J. Pierzynski's foot before stumbling into a dive beyond the plate.
Sanchez had doubled and advanced to third on a Jordy Mercer single.
The Pittsburgh scoring continued in a three-run, four-hit fifth inning. All three runs scored with two outs.
Jordy Mercer doubled down the left field line, and an error from Craig Gentry turned it into a three-bagger. Mercer came home on a single by Andrew McCutchen.
After a two-out single by Marlon Byrd moved McCutchen to second, Gaby Sanchez scored McCutchen from second with a single to left field. A good throw would have had even the speedy Pirate center fielder, but Gentry's throw went 10 feet up the first baseline.
Perez threw a wild pitch in the next at-bat, which scored Byrd from third.
The Rangers snapped a 15-inning scoreless streak in the bottom half of the fifth inning, when Ian Kinsler lined an RBI double off the glove of a sliding McCutchen in center field.
Joey Butler, after his first of two walks on the night, scored on the play. Butler's on-base percentage stands at .667 in five major league games in 2013.
The second Ranger run came home in the eighth inning, when Beltre slapped an RBI single to right field to score Rios, who doubled in the previous at-bat.
Rios has five multi-hit games already in the month of September, and has hit safely in 22 of his 28 games with the Rangers. He also singled and stole second base in the first inning.
Perez entered the game having allowed 14 earned runs over 49.2 innings pitched in last seven starts. Perez's two strikeouts Tuesday matched his season low. He also recorded just two punch-outs in his first start of the year on May 27.
The five-plus innings for Perez marked the shortest outing for the rookie southpaw since July 26, when he threw just three innings against Cleveland. That game also happened to be Perez's last loss.
Francisco Liriano started for the Pirates, throwing six innings and allowing only one run while striking out five.
Four relievers succeeded Liriano for the Bucs, including Mark Melancon, who recorded save no. 13 of the season despite surrendering two ninth-inning runs.
Four Ranger pitchers relieved Perez as well. The fifth run was an inherited runner from Robbie Ross, who walked the only batter he faced Tuesday.
The Rangers didn't lose any ground in the division despite the loss, as the Oakland A's lost in Minnesota, 4-3. The deficit stayed at two games in the AL West.
The third and final game with Pittsburgh is slated for 1:05 p.m. Wednesday before Oakland comes to Arlington for a pivotal three-game series Friday.