Hand it to the Pittsburgh Pirates, who waited out the Los Angeles Dodgers until the most vulnerable part of their team showed itself: The bullpen.

The Pirates scored nine runs in the seventh inning Sunday night, eight against right-hander Jim Johnson in a 13-6 victory that completed a three-game sweep at PNC Park, and cast further doubt on the Dodgers bullpen, which has gotten progressively worse this season.

Dodgers relief has a 7.94 ERA this month, after posting a 6.27 ERA in July. Even in June, when it was 4.00, it wasn't that good. The long ball is really hurting them; Dodgers relievers have allowed 28 homers spanning 172 1/3 innings since June 1. They allowed six homers over 137 1/3 innings in April and May.

Enter: Jung Ho Kang. After getting hit with a pitch to start the rally, Kang hit a three-run homer to cap the scoring in the seventh, which the Dodgers began with a 5-3 lead after left-hander Alex Wood made it through five innings and reliever Juan Nicasio pitched a scoreless (but rocky) sixth. Dodgers manager Don Mattingly turned to Johnson, who had been part of a three-team deal that L.A. made with the Braves in order to bolster its pitching staff (among other motivations). This is what happened when Johnson -- who came in with a 12.00 ERA in three innings since the trade -- faced 10 Pirates batters:

Aramis Ramirez: struck out looking.

Kang: hit by pitch.

Pedro Alvarez: single to right, runners advance to second and third on Yasiel Puig throwing error

Francisco Cervelli: RBI single, Alvarez to third. Dodgers 5-4.

Neil Walker: Sacrifice fly. Score tied 5-5.

Sean Rodriguez: singled.

Gregory Polanco: walked to load bases.

Starling Marte: Infield RBI single. Pirates lead 6-5.

Andrew McCutchen: Two-run single. Pirates lead 8-5.

Ramirez: RBI single. Pirates lead 9-5.

Joel Peralta relieves Johnson.

Kang: Three-run homer. Pirates lead 12-5.

Here's the carnage on video. Reporter J.P. Hoornstra of the Los Angeles Daily News says that Johnson's appearance was historically bad:

The Dodgers were trailing the Pittsburgh Pirates 5-1 on a Monday afternoon at Forbes Field in 1933 when a relief pitcher named Fred Heimach entered the game and allowed nine runs while recording one out.

For 82 years, no Dodgers reliever allowed as many as eight runs while recording fewer than three outs until Sunday. Five miles away from the site of Forbes Field, it happened again.

The Pirates won their fourth straight to improve to 65-44, five games back of the Cardinals in the NL Central, but are firmly in place as a wild-card leader. McCutchen continued to rev his engine, as the Associated Press points out, hitting a two-run homer against Wood in the fifth to bring the Pirates within 5-3:

McCutchen is hitting .455 with 13 RBIs and 12 runs scored in his last 10 games and .410 with runners in scoring position this season.

''I don't know, it's so hard for me to say,'' McCutchen said when asked if he could remember a better stretch of hitting. ''I still don't think I'm completely where I want to be.''

As dire as the Dodgers bullpen situation seems, they had won seven of eight before getting to Pittsburgh. They lost the first two games of the Pirates series by one run apiece, and they blasted 14 hits in the finale. They're still in first place in the NL West by three games, because the Giants sustained a four-game sweep at Wrigley Field.