PITTSBURGH - No matter what interim manager Pete Mackanin accomplishes in the Pittsburgh Pirates' final 26 games, he can't prevent their 13th consecutive losing season.

Rookie catcher Ryan Doumit's errant throw on a rundown play in the 12th inning got Pete Mackanin's managerial run in Pittsburgh off to a losing start, a 4-2 defeat to Arizona that was the Pirates' 82nd of the season.

While Arizona ended a five-game losing streak, the Pirates dropped their fifth in a row, 10th in 11 games and 15th in 19 games - a slide that caused manager Lloyd McClendon to be fired earlier in the day. Mackanin, a 13-year minor league managing veteran and the bench coach, succeeds McClendon for the rest of the season.

"It would have been nice to win the first one," said Mackanin, who was cheered by the small crowd before the game. "You do everything you can think of to put guys in position to score some runs, to have the pitchers out there who give you the best chance of winning, and hope they pull it out."

As usual, they didn't.

The game-winning run came on a play that illustrated why both teams have been stuck in long slides since several months into the season, when both were playing .500 ball. The Pirates have lost nine in a row at home, their longest streak since PNC Park opened in 2001.

With Chad Tracy on second, Chris Snyder singled to right to end an 0-for-21 streak. Tracy was halfway down the line at third when he realized he would be out easily. As he scrambled back to third, Doumit's throw struck him in the lower left shoulder and bounded away, allowing him to score.

Royce Clayton followed with an RBI single off John Grabow (2-2) as Arizona won despite being outhit 15-7.

Pirates rookie left-hander Paul Maholm, making his second start, ran his start-of-career scoreless streak to 11 innings before giving up Troy Glaus' RBI double in the fourth. Maholm pitched eight innings in beating Milwaukee 6-0 on Aug. 30, in what turned out to be McClendon's final win as manager.

Brad Eldred and Ty Wigginton each hit their seventh homers to put Pittsburgh up 2-1 against Javier Vazquez, who allowed 12 hits but only two runs in six innings as the Pirates stranded 10 runners.