The Pittsburgh Pirates came into Cleveland with a four-game winning streak. After a lost weekend, they headed home on a three-game slide.

Cord Phelps hit his first major league homer in the 11th inning off Tim Wood, a three-run shot that gave the Indians a 5-2 victory Sunday and a sweep of the interleague series.

The loss also dropped Pittsburgh under the .500 mark at 35-36.

"I didn't go to college, but I can kind of count to 35 and 36 and up to 40, so I have an idea of where we are," manager Clint Hurdle said. "I'm not hawking the board. I'm not picking up the stat sheet every day to find out where we are. We need to focus on the game we're playing. That's one thing we've talked about long and hard. We have a 162-game season."

After taking a 2-0 lead in the first, the Pirates were shut down for the final 10 innings. Pittsburgh, which managed four runs in the series, had 11 hits but couldn't come through in the clutch.

"We left 14 men on base," Hurdle said. "At the end of the day, that's a lot."

Neil Walker and Matt Diaz drove in first-inning runs off Justin Masterson to put Pittsburgh ahead.

Walker followed a one-out triple by Xavier Paul with an RBI single. Walker took third on a single by Garrett Jones and scored as Diaz grounded into a forceout at second.

The Indians tied the game in the second on Carlos Santana's solo homer and a double-play grounder by Lou Marson. The game, delayed by rain in the eighth inning for 1 hour, 57 minutes, remained that way until Wood (0-1) came on to start the 11th.

Shin-Soo Choo singled with one out for his third hit and stole second. Wood intentionally walked Santana to bring up Phelps, who came to bat hitting .100 (2 for 20) since being called up from Triple-A Columbus on June 8. The rookie hit an 0-1 pitch into the seats in right field.

"That's my first walk-off of any kind, at least that I can recall," said Phelps, mobbed at the plate by teammates. "That was awesome. Really cool."

Wood took full responsibility for the loss.

"It was a fastball in," he said. "He did exactly what he's supposed to do with a belt-high fastball."

Wood said he faced Phelps while pitching for Triple-A Indianapolis earlier this season.

"I had faced him a few times and got him out," he said.

Tony Sipp (3-0) worked a scoreless 11th to help the Indians win for the fifth time in seven games and move to 6-0 in interleague play. Their sweep extended the Pirates' losing streak to 13 games in AL ballparks.

Pittsburgh, which returns home to face Baltimore on Monday, has not won a road interleague game since June 17, 2009, at Minnesota.

The Pirates swept three games in Houston to begin their road trip.

Pittsburgh starter Jeff Karstens gave up one earned run and five hits over seven innings. The right-hander has not allowed more than two earned runs in a game since May 3, a stretch of nine starts.

Hurdle said Karstens would have come back for the eighth inning if not for the rain delay. The umpires called for the tarp after the Pirates were retired in the top of the inning.

"I really didn't have any idea what was going on," Karstens said. "I didn't have time to be disappointed. Unfortunately, we came up on the wrong side again."

Santana hit Karstens' first pitch of the second inning into the right-field seats for his ninth homer. Phelps doubled on the next pitch, moved up on a passed ball and later scored when Marson bounced into a double play, tying it at 2.

"I know I was king of the at-'em ball," Karstens said. "They had a pretty good approach early."

Before the game, the Indians announced that hitting coach Jon Nunnally, who played in the Pirates' farm system from 2004-05, had been replaced by Bruce Fields, the organization's minor league hitting instructor.

NOTES: Hurdle moved CF Andrew McCutchen, who was the DH on Sunday, from third to the leadoff spot while Walker was bumped from cleanup to third. ... Pirates first base coach Luis Silverio stayed in the game after being hit in the inner thigh by a foul line drive off the bat of Jones in the fourth. .. Indians SS Asdrubal Cabrera got a standing ovation after making a barehand stop on the outfield grass and throwing out Brandon Wood in the top of the 10th.