Sanchez had Pittsburgh's first six-hit game in 19 years, scored four runs and drove in three Monday, leading the Pirates to a 10-8 victory and sending Chicago to its eighth straight loss.
"At the last minute when I was making out the lineup, I decided to put him in," Pirates manager John Russell said. "I guess it was smart of me."
And painful for the Cubs.
Despite scoring three more runs than they did on the entire winless six-game road trip that ended Sunday, they fell to 21-22 and were booed repeatedly by their fans.
The last time the Cubs dropped eight straight was 2006, when they went on to finish 66-96, costing manager Dusty Baker and team president Andy MacPhail their jobs.
"It's good to see the team swinging the bats and I hope that continues," Cubs manager Lou Piniella said. "We've just got to start winning a few games, that's it."
Sanchez hit a two-run homer, doubled and singled four times for the second six-hit game in the majors this season and the first by a Pirate since Wally Backman did it in 1990. Ian Kinsler had a six-hit effort for Texas on April 15 against Baltimore.
"Six hits ... that's good for a series worth," said Nate McLouth, who hit the go-ahead homer -- with Sanchez on base -- in the sixth inning.
Sanchez has snapped out of a 5-for-36 slump by getting nine hits in his last 15 at-bats.
"I was striking out too much before," he said. "I shortened my swing and put the ball in play. It's tough to get hits in this game. I just want to keep it going."
One day after getting 16 hits at U.S. Cellular Field, Pittsburgh had a season-high 18 at Wrigley Field.
The Cubs won the NL Central the last two years, have a $135 million payroll and came into this season as prohibitive division favorites. Starter Ryan Dempster, who allowed six runs in four innings, said the players remain confident.
"We're not worried about the eight previous games; we're just worried about winning the next one," he said. "Just do the same thing we did tonight and get a little better job out of the starting pitcher. I let those guys down."
After Neal Cotts (0-2) allowed McLouth's homer in the sixth, he gave up doubles to brothers Adam and Andy LaRoche for a 9-7 lead. In the seventh, Nyjer Morgan tripled and scored on Sanchez's single to put the Pirates up by three.
The Cubs got a run back in the seventh off Tom Gorzelanny (2-1) and had two on when Jesse Chavez struck out Carlos Zambrano to end the threat. Piniella used Zambrano, a pitcher, as a pinch-hitter even though position players Kosuke Fukudome, Mike Fontenot and Koyie Hill were available.
After regular Pirates closer Matt Capps was knocked out of the game in the ninth when struck in the right (pitching) elbow by Geovany Soto's line drive, Sean Burnett got the final two outs for his first career save. Capps was taken to a hospital for X-rays; results were not immediately available.
Chicago's Milton Bradley had a season-high four RBIs. A $30 million free agent acquisition who had been doing more complaining about umpires than hitting, he went into Monday batting .188 with nine RBIs.
"Getting on umpires is not a good solution," Piniella said before the game. "What we need Milton to do is ... [hit] the ball the way he has in the past."
Bradley responded with a two-run double in the third and a two-run homer in the fourth.
Ryan Theriot had three doubles for the Cubs. ... Pittsburgh starter Paul Maholm allowed seven runs in four innings. ... Cubs 1B Derrek Lee and utility infielder Bobby Scales were scratched from the lineup with the flu. Scales flied out as a pinch-hitter in the fourth but Lee was sent home before the game. ... Cubs reliever Carlos Marmol went to New York to be with his wife, who is scheduled to give birth to their second child on Tuesday. ... Andy LaRoche had three hits and is batting .447 during a 10-game hitting streak. ... Ted Lilly, who started Sunday's game at San Diego for the Cubs, was ejected in Monday's fifth inning for complaining about ball-strike calls from the dugout.