BALTIMORE -- A two-game series that was scheduled to end Wednesday stretched into early Friday morning before Matt Wieters finally put an end to the rain-marred interleague matchup between the Pirates and Orioles.
Wieters led off the 10th inning with a home run off Stolmy Pimentel to give Baltimore a 6-5 victory and a doubleheader sweep Thursday night.
The single-admission doubleheader followed consecutive rainouts Tuesday and Wednesday. The rain lingered long enough to delay the fifth inning of the opener by 21 minutes, and the start of the nightcap was stalled 46 minutes by rain.
The second game lasted 3 hours, 57 minutes. By the time it ended, the clock had ticked well past midnight.
"It's not a late night, it's an early morning," said Orioles reliever Darren O'Day, who pitched in both games.
As O'Day spoke, the team had 30 minutes to get ready for a trip to Minnesota for a three-game series that was to begin Friday night.
"It will be a happy flight," O'Day said, "so that will make it a little easier."
The second game marked the season debut of Orioles third baseman Manny Machado, who had left knee surgery in October. After sitting out the opener, Machado received a warm ovation from the crowd of 28,290 before the second game and went 0-for-5.
Baltimore trailed 4-0 in the nightcap before rallying with a four-run sixth. Adam Jones doubled in a run and scored on a single by Wieters before Pearce chased starter Brandon Cumpton with a double to right. Bryan Morris entered and yielded a two-run double to J.J. Hardy.
Starling Marte countered with an RBI single in the seventh for Pittsburgh, but Markakis tied it in the bottom half with a solo shot off Morris.
Wieters won it in the 10th with a drive to right off Pimentel (2-1) that soared just inside the foul pole.
Tommy Hunter (1-0) got two outs for the win.
Earlier, Baltimore ace Chris Tillman struggled through a 49-pitch first inning that could be attributed in part to a seven-day layoff. The right-hander issued three walks, two with the bases loaded, before getting three outs.
Pedro Alvarez had four hits for the Pirates, finishing a home run short of the cycle. But Pittsburgh stranded 15 and went 5-for-16 with runners in scoring position, and lost for the 15th time in 19 games.
"We keep fighting and fighting, and we put ourselves in scoring position and we haven't been able to cash in the way we need to," manager Clint Hurdle said. "But we keep showing up. The bats were better throughout the series. ... We had men on base throughout the game, and still looking for that big hit."
The first game was all about Pearce, designated for assignment by Baltimore on April 22 and released five days later. After turning down an offer from Toronto, the first baseman was re-signed Monday after Chris Davis went on the 15-day disabled list.
Pearce singled in the third, fifth and sixth innings of the opener, and was solid in the field.
"Stevie gave us a real lift," manager Buck Showalter said.
Alvarez had two hits and an RBI for the Pirates, who stranded 13 and went 1-for-14 with runners in scoring position. The defeat ended Pittsburgh's nine-game road winning streak in interleague play.
Trailing 1-0 when the rain stopped play, Baltimore regrouped during the break and sent nine batters to the plate in a three-run fifth. After a single, a walk and an error loaded the bases against Charlie Morton (0-4), Pearce hit an RBI single and Ryan Flaherty grounded an opposite-field, two-run single to left field.
Pearce singled in a run in the sixth, and Markakis hit his first homer of the season in the seventh for a 5-1 lead.
Orioles starter Bud Norris (2-2) allowed one run in 5 1/3 innings, and Hunter got the last out with runners on second and third for his seventh save.
Morton started well but came unhinged after the rain delay and lost his fourth consecutive start. The right-hander permitted four runs, two earned, and seven hits in 5 1/3 innings.
"I kept grooving fastballs to Steve Pearce and he kept putting good swings on them," Morton lamented.
Pittsburgh returns home to face Toronto on Friday night. ... Orioles LHP Troy Patton returned from a 25-game suspension before the second game. Baltimore also activated Machado from the DL, and optioned INF Steve Lombardozzi and RHP Josh Stinson to Triple-A Norfolk. ... The last time Pittsburgh played a doubleheader on the road was in July 2011, at Washington. ... Pirates LHP Wandy Rodriguez (right knee inflammation) allowed three runs and four hits over 3 1/3 innings in a rehabilitation assignment for Double-A Altoona against Erie. ... Baltimore's rainout against Tampa Bay on April 15 was rescheduled as part of a split doubleheader June 27.