The San Diego Padres have gone 7-13 since Pat Murphy took over for the fired Bud Black. Still, the interim manager remains optimistic.

Gregory Polanco helped free a grounds crew member trapped underneath a billowing tarp, then hit a go-ahead triple that sent the Pittsburgh Pirates past the Padres 3-2 Tuesday night.

San Diego lost its fourth straight game and was held to two runs or fewer for the seventh time in eight games.

"I'm not ready to give up on the idea that we can turn things around," said Murphy, who was manager of the Padres' Triple-A El Paso farm club until being promoted June 16. "We're playing good teams and we're a little snake bit right now. Things will turn."

It was 2-all when Sean Rodriguez was hit by pitch from Joaquin Benoit (5-4) leading off the eighth. The .232-hitting Polanco tripled with two outs, giving the Pirates their fourth straight win.

Polanco, Rodriguez and fellow Pirates outfielder Andrew McCutchen made the play of the game at the start of a 1 hour, 42 minute rain delay in the top of the third inning.

Strong winds and rain caused the tarp to start swelling as the grounds crew at PNC Park struggled to cover the infield, and a worker was swallowed up. McCutchen, Polanco and Rodriguez came from the dugout to help pull the tarp off him.

"Get him out as quickly as possible," Rodriguez said when asked about his first reaction. "Some people are going to be claustrophobic immediately and start to kind of struggle a little bit. Right away I didn't know he was going to come out as calm as he did. I was just thinking pull off as much tarp as I can and see if I can lighten up whatever might have wrapped him up."

Matt Kemp doubled in both Padres' runs in the third after resumed but the Padres never scored again.

Kemp and Clint Barmes had two hits apiece for the Padres.

"We've pretty solid baseball for the most part all season but we just seem to have a hard time finding a way to win the close games," Barmes said. "You look at this lineup and it's a little baffling why we haven't scored more runs. It's not for a lack of effort."

Padres starter Tyson Ross was pulled after the delay. He worked two scoreless innings.

McCutchen doubled, singled and set a career high by extending his hitting streak to 14 games. He had a 13-gamer as a rookie in 2009.

Tony Watson (2-1) pitched a scoreless eighth and Mark Melancon worked the ninth for his NL-leading 28th save.

McCutchen doubled home a run in the third and Jung Ho Kang tripled in the tying run in the fifth.

Pittsburgh starter Francisco Liriano allowed two runs and four hits in six innings with six strikeouts and a walk.