CHICAGO — Jason Bay and the Pittsburgh Pirates don't plan to celebrate their move out of last place for long.

Bay homered twice and Jose Bautista scored the go-ahead run in the ninth inning on a wild pitch as the Pirates escaped the cellar in the NL Central with a 6-5 victory over the Chicago Cubs on Tuesday night.

The Cubs (55-83) have lost five straight against the Pirates (56-83) and fell behind Pittsburgh into last place in the division for the first time this season.

The Pirates started the season 0-6 and had sat at the bottom all year.

"It's a little moral victory for us," Bay said. "You don't want to run around and throw a party because you got out of last place."

The Pirates have won six of eight, while Chicago lost for the 15th time in 18 games and now own the worst record in the National League.

"It's tough to be out there, playing in a game, people are saying it's the two worst teams. It's not fun," Cubs first baseman Derrek Lee said. "It wasn't expected, that's for sure. We thought we had a good team going into the spring. Obviously, we had some different circumstances this year, but we are still expected to play better than this."

With two outs in the ninth and Bautista on first, Cubs closer Ryan Dempster (1-8) walked Freddy Sanchez and Bay to load the bases. On the first pitch to Xavier Nady, Dempster threw a wild pitch, allowing Bautista to score and giving the Pirates a 6-5 lead.

John Grabow (4-1) pitched a scoreless eighth for the victory. Salomon Torres got the final three outs for his third save.

Pittsburgh earned its first season-series win over Chicago since 2000 when the Pirates took nine of 12 games. The Pirates are 8-5 against the Cubs this season.

The crowd of 31,494 was the Cubs' smallest at home this season.

"This is one of many low points of the year, actually. We just have to keep playing. We have these guys the next two days," Cubs manager Dusty Baker said.

Bautista singled in the first inning off Cubs starter Juan Mateo. With two outs, Bay homered for the 30th time this season to put the Pirates up 2-0. Bay became the second right-handed hitter in club history to hit at least 30 home runs in consecutive seasons. Hall of Famer Ralph Kiner reached the mark in six straight seasons from 1947-52.