Cubs starter Ryan Dempster finally got some run support, but coupled by his worst outing of the season, the beleaguered starter remains winless on the year.
Chicago, however, was still able to gut out its third consecutive win for the first time all season.
Darwin Barney smacked a two-run homer in the bottom of the ninth inning, lifting the Cubs over the San Diego Padres, 8-6, in the finale of a three-game set.
Barney finished 2-for-3 with three RBI and three runs scored for Chicago, which plated all eight of its runs with two outs and rallied from a three-run fifth-inning deficit.
Dempster surrendered a season-high six runs on six hits and four walks in 4 1/3 frames. Coming into the game, the Cubs had scored an average of 1.98 runs per 9.0 innings pitched for Dempster this season, the second lowest average in the majors.
"I just kept putting us behind the eight ball and they just kept battling back," Dempster said. "That was outstanding, Barney hitting that walkoff."
James Russell (2-0) earned the win with a scoreless ninth.
Carlos Quentin clubbed a pair of two-run homers for the Padres, who have lost six straight and nine of their last 10.
The Cubs plated a pair in the fifth on consecutive bases-loaded walks, and with the Padres clinging onto a 6-5 lead in the eighth, the Cubs mustered another two-out rally to tie the score.
"I think with (Padres starter) Anthony [Bass], he was trying to make too good of a pitch," San Diego manager Bud Black said. "His left shoulder was flying open a touch and his stride got a little bit long."
Reed Johnson singled and was replaced on the basepaths by Tony Campana, who stole second and third before David DeJesus walked. Starlin Castro beat out a high chopper to third as Campana sprinted home.
Bryan LaHair began the ninth with a single up the middle off of Dale Thayer (0-1). After Alfonso Soriano struck out and Ian Stewart flied out, Barney drilled a 1-2 slider over the wall in left-center for the win.
Earlier, the Padres struck first with two runs in the second. Chase Headley led off with a single and Chris Denorfia followed and ripped a two-run shot to left.
A pair of RBI singles by Steve Clevenger and Dempster tied the score in the home half, but San Diego regained its advantage in the third.
Everth Cabrera laced a leadoff double to left and after Yonder Alonso fanned, Quentin laced a two-run blast to left for a 4-2 San Diego lead.
Clevenger's run-scoring double in the fourth cut the deficit to 4-3, but the Padres retaliated with another two-run frame in the fifth.
Alonso walked to begin the inning and Quentin ripped an opposite-field two-run shot to right, extending the San Diego margin to 6-3.
Dempster has now gone 18 total starts without a win. The last Cubs starter to go that many outings without a victory was Danny Jackson, who went 20 from June 19, 1991-May 31, 1992...Chicago last won three in a row on Sept. 10-12, 2011...Bass allowed five runs on six hits and four walks in 4 2/3 innings.