“Either I strike him out or he hits a home run,” Zambrano said. “You can’t make a mistake against a hitter like that, they make you pay.”

Zambrano (10-7) limited the Pirates to four hits over seven innings — they had two harmless singles in the fourth — but still lost for the first time in four decisions. He also missed out on what would have been an NL-leading 11th victory, losing to Pittsburgh for the second time this season.

“I had a rough time in the first two innings with my windup,” said Zambrano, who didn’t feel comfortable on the mound until making an adjustment following Bay’s homer. “I changed my delivery right after that.”

Youman is 2-0 since being called up from Triple-A Indianapolis for his only two career victories, furthering the Cubs’ problems against left-handed starters, who are 14-8 against them. He allowed plenty of base runners — eight in six innings — but worked his way out of major problems with minimal damage several times.

“That’s what they’ve preached to me since the low minors, damage control,” Youman said. “Making guys swing the bats without too much happening.”

Aramis Ramirez, Mark DeRosa and Mike Fontenot singled to load the bases with none out in the second, but Youman got the next two hitters following Angel Pagan hit a sacrifice fly. DeRosa doubled as the Cubs put three of their first four batters on base in the sixth, but Ramirez grounded into a double play and Fontenot grounded out.

Shawn Chacon replaced Youman and retired all six batters he faced before Matt Capps pitched the ninth in a non-save situation.

Notes: The Pirates have won six of eight series. ... The Cubs had won four consecutive series. They remain 4½ games back in the NL Central as division leader Milwaukee lost 7-2 in Washington. ... Cubs SS Ryan Theriot and 2B Fontenot were College World Series-winning teammates of Youman’s at LSU in 2000. ... Zambrano had won his last six road decisions. ... Chicago came into the series winning 21 of 31.

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