Pittsburgh Pirates' Jake Mangum celebrates after scoring on a single by Brandon Lowe off Arizona Diamondbacks pitcher Merrill Kelly during the sixth inning of Monday’s baseball game in Pittsburgh. Associated Press

PITTSBURGH — Brandon Lowe singled home Billy Cook in the bottom of the 10th inning to rally the Pittsburgh Pirates to a 3-2 win Monday night over the Arizona Diamondbacks.

Lowe finished a three-hit night by lacing a line drive off Diamondbacks reliever Taylor Clarke (2-2) that smacked off the glove of Arizona first baseman Ildemaro Vargas and rolled away, allowing Cook to race home as the Pirates pulled even with the Diamondbacks for the National League's third wild-card spot.

Mason Montgomery (4-3) worked around an error by third baseman Nick Gonzales and escaped a bases-loaded jam in the top of the 10th to earn the victory. The Pirates' bullpen, which has been a sore spot much of the season, tossed 4 2/3 scoreless innings.

Bryan Reynolds delivered a game-tying RBI double in the eighth for Pittsburgh, which lost promising rookie outfielder Esmerlyn Valdez to a left-hand injury in the fourth inning after getting hit in the left wrist with a 92 mph fastball by Arizona starter Merrill Kelly.

The 22-year-old Valdez, who entered Monday with 24 RBIs in July and 14 home runs this season, winced in pain while being tended to by medical staff. He walked slowly toward the Pittsburgh dugout and was replaced by Jared Triolo.

Kelly allowed one unearned run in 5 2/3 innings, walking one and striking out six while lowering his ERA to 4.86, the lowest it has been since early April.

Pittsburgh's Mitch Keller had his second straight solid start coming out of the All-Star break, giving up two runs in 5 1/3 innings, his only real mistake coming in the sixth when three singles loaded the bases, and Max Kepler followed with a rope to the corner in right that gave the Diamondbacks the lead.

Kepler finished with three hits for the Diamondbacks, who lost for just the fifth time in 15 games. Arizona catcher Gabriel Moreno went hitless in four at-bats but extended his on-base streak to 24 games with a first-inning walk.

The series continues Tuesday when Arizona's Brandon Pfaadt (5-1, 4.43 ERA) gets the start against Pittsburgh's Bubba Chandler (3-8, 4.47).