The struggling closer pitched a perfect 10th inning after Adam LaRoche singled in the tiebreaking run in the top half, and the Pirates won 5-4 Sunday to salvage the finale of a wild three-game series.
Pittsburgh frittered away a five-run lead Friday night, and Capps lost a 7-6 advantage in the ninth inning Saturday. The pattern continued Sunday, when Capps yielded a two-run homer to Brian Roberts in the ninth to force extra innings.
But after botching his third save opportunity in four games, Capps was determined to make amends in the 10th.
"I wanted it. Whatever the situation. Whether it was still tied or we had scored 10 runs or one run like we did, I wanted it," the right-hander said.
Capps struck out Kevin Millar, retired Aubrey Huff on a grounder and ended the game with a strikeout of Adam Jones.
"Obviously it would have been a whole lot better to have the game end in the ninth inning," Capps said. "But I am what I am. I am who I am."
Nate McLouth homered and made a spectacular catch in center field for the Pirates, who ended a seven-game skid in interleague play with their first win against an AL team since June 19, 2007, at Seattle.
Baltimore closer George Sherrill (2-2), who blew a save opportunity Saturday night, opened the 10th by walking Jason Bay. After a single by Ryan Doumit put runners on the corners, Jason Michaels struck out before LaRoche singled to right.
"I guess it just shows you he's human. It happens to the best of them," Orioles manager Dave Trembley said of Sherrill, whose ERA rose from 2.73 to 3.48 over the weekend.
Guillermo Quiroz and Aubrey Huff hit solo shots for the Orioles, who rallied from a 4-0 hole but lost their 10th straight Sunday game. After winning on the first Sunday of the season, Baltimore has since been outscored 55-26 on that day.
The Orioles trailed 4-2 in the ninth when Pittsburgh manager John Russell summoned Capps. Oscar Salazar led off with a sharp grounder to third that Jose Bautista misplayed, ending Pittsburgh's season-long run of 73 straight errorless innings.
Capps (1-2) then got two outs before Roberts hit an opposite-field drive that barely cleared the left-field wall.
"After he hit that home run, momentum was back on our side," Baltimore's Jay Payton said. "And the way we've been going, we kind of felt we might be able to sneak that one out."
But the Pirates rebounded in the 10th, and the Orioles couldn't mount another comeback in their half.
"I've never seen nothing like it, two teams keep coming back at each other," Russell said. "It was an amazing series."
Pirates starter Paul Maholm gave up two runs and four hits in six-plus innings. The left-hander was lifted after giving up a leadoff walk to Salazar in the seventh.
The Orioles then got runners to second and third with one out against John Grabow, but Roberts struck out before McLouth sprinted in and dived headfirst to snare a potential tying blooper by Payton.
"I thought it was definitely going to fall," Payton said.
"That was a huge play for us," Russell said. "Nate continues to lift us in different ways all the time."
Baltimore starter Daniel Cabrera allowed four runs, six hits and five walks in six innings. The struggling right-hander also hit two batters, threw a wild pitch and failed to retire the side in order. In his last five starts since May 20, Cabrera is 0-1 with a 6.68 ERA.
Pittsburgh went up 3-0 in the third. After McLouth led off with his team-high 15th homer, Bay walked and Doumit was hit by a pitch. Both advanced on a wild pitch and scored on a single by Michaels. Cabrera then hit LaRoche with a high fastball, and LaRoche took a step toward the mound before going to first base.
An RBI single by Bautista made it 4-0 in the fifth. Quiroz homered in bottom half and Huff connected in the sixth.
Orioles 3B Melvin Mora was scratched from the starting lineup because his left leg was still swollen after he hit a foul ball near his knee Saturday night. He flied out as a pinch hitter. Also, reliever Dennis Sarfate missed the game after his wife gave birth Sunday morning. ... Pirates OF Xavier Nady did not play after bruising his left shoulder Saturday chasing a foul ball. He is expected to receive an MRI exam in Pittsburgh on Monday.