Colin Moran hit a two-run homer that capped a four-run rally against Nate Jones in the ninth inning, leading the Pirates over Chicago 6-5 on Wednesday and sending the last-place White Sox to their ninth loss in 10 games.
Pittsburgh trailed 4-0 for the second straight night before rebounding for its 10th comeback victory.
''We've got each other's backs,'' Pirates shortstop Jordy Mercer said. ''We created that chemistry in spring training. And we've got nothing to lose. Everybody picked us to be last and tank and not be good. So we just go out and have fun and play.''
Chicago took a 5-2 lead into the ninth behind Reynaldo Lopez, who allowed two runs and three hits in a career-high 7 1/3 innings.
Jace Fry struck out the final two batters of the eighth, but Jones (2-1) blew a save for the second time in three chances as the White Sox lost their fifth in a row and fell to 9-25. Chicago is off to its second-worst 34-game start behind an 8-26 opening in 1948.
The White Sox have the poorest home record in the major leagues at 3-15 - the worst 18-game home start in franchise history. Chicago has lost six consecutive home series for the first time since 1971.
''I couldn't have scripted it any better today,'' White Sox manager Rick Renteria said. ''We did exactly what we wanted to do, got to the back end of the game. We had the guy we wanted to close it out, and we didn't. That's it. We played a really good ballgame, I thought.''
Starling Marte and Josh Bell singled on consecutive pitches off Jones, Corey Dickerson grounded out and Elias Diaz cut the lead to one with a two-run double on an 0-2 pitch.
Moran took a ball and then drove a slider 416 feet to right-center.
''I got that one as good as I could,'' Moran said. ''It was in a good zone to hit, so I took a swing.''
Richard Rodriguez (1-1) won despite allowing consecutive doubles to Jose Rondon and Welington Castillo in the eighth. Felipe Vazquez pitched a perfect ninth for his seventh save in seven chances.
Mercer and Gregory Polanco hit solo home runs in the sixth that cut Chicago's lead to 4-2. Mercer also threw out Jose Abreu at the plate from just outside the infield dirt trying to score from second on a single, ending the third.
Tim Anderson and Daniel Palka hit two-run homers for the White Sox.
Pittsburgh starter Trevor Williams allowed a season-high four runs and seven hits in five innings.
Pirates: RHP Joe Musgrove (right shoulder strain) is expected to make his next start for Triple-A Indianapolis. He pitched four scoreless innings for Double-A Altoona on Monday.
White Sox: 3B prospect Jake Burger has torn his left Achilles tendon again and will be sidelined for an additional year. Burger first tore the tendon Feb. 26 while running out a ground ball during an exhibition game against Oakland. White Sox general manager Rick Hahn said the 22-year-old re-injured the tendon last week while walking in his backyard and had surgery Tuesday. ... OF Nicky Delmonico (bruised right quadriceps) left in the fifth, two innings after colliding with Pirates 1B Josh Bell while rounding the base on a single. ... 2B Yoan Moncada (left hamstring tightness) took ground balls before the game. The team is optimistic that can be activated from the 10-day DL when eligible on May 15.
Pirates: RHP Jameson Taillon (2-3, 4.42) started Friday at San Francisco. He is 0-3 in his last five starts.
White Sox: RHP Carson Fulmer (2-2, 5.02 ERA) starts Friday at Wrigley Field.
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