SAN DIEGO – Alfonso Soriano homered twice, including a two-run shot off struggling San Diego ace Mat Latos, and the Chicago Cubs won 5-2 on Tuesday night to drop the wilting Padres 1½ games behind Atlanta in the NL wild-card race.
The 22-year-old Latos, who fumed after the Cubs scored two unearned runs in the fifth, lost his fourth straight start, his worst stretch this season.
The Padres have lost 21 of 32 games since Aug. 25, when they were 76-49 and had a 6½-game lead over the Giants in the NL West. The Padres dropped two games behind the Giants, who beat Arizona 4-2. After two more games against the Cubs, the Padres will close the season with three games at San Francisco.
Chicago's Ryan Dempster and two relievers combined on a four-hitter. Dempster (15-11) struck out nine in seven innings. Carlos Marmol pitched the ninth for his 36th save in 41 chances, and his 20th since the All-Star break.
The Padres were four-hit in a 1-0 loss to Carlos Zambrano and the Cubs on Monday night.
Before his skid, Latos (14-9) set a major league record with 15 straight starts of five or more innings with two or fewer runs allowed. In his last four starts, he's allowed 18 earned runs in 16 innings, and hasn't made it out of the sixth inning.
With the score tied at 2 and Xavier Nady aboard on a leadoff single in the sixth, Soriano homered into the Padres' bullpen beyond the fence in left-center. It was his 23rd. Latos got Blake DeWitt to fly out to left, then was hit on the right calf by Koyie Hill's comebacker, which went for an infield single. Latos stayed in the game, allowed Dempster's sacrifice bunt and then was pulled in favor of lefty Joe Thatcher, who got the final out.
Soriano homered again on full-count pitch from Mike Adams leading off the eighth.
Latos allowed four runs, two earned, and seven hits in 5 2-3 innings. He struck out six and walked two.
A Padres' defensive meltdown led to the Cubs scoring two unearned runs in the fifth. Latos fielded Hill's one-out bunt but dropped it for an error. Dempster sacrificed over Hill, who scored on Kosuke Fukudome's double to left-center. Starlin Castro beat out an infield single deep in the hole at shortstop as Miguel Tejada tried to make a twisting, off-balance throw. The ball skipped past sprawling first baseman Adrian Gonzalez and into the Padres' dugout, allowing Fukudome to score.
An upset Latos was yelling at someone in the dugout after the inning.
San Diego's Nick Hundley tied it at 2 with a 398-foot home run on a full-count pitch from Dempster into the second deck in left field, his eighth. Chase Headley was aboard on a one-out walk.
Moments after homering, Hundley tried to calm down Latos in the dugout.
At nearly the exact moment Hundley connected, Juan Uribe hit a trying solo home run leading off the fourth to pull the Giants into a 2-2 tie.
Dempster allowed four hits and walked two. The Padres had two runners on and no outs in the seventh before Dempster struck out the side.
NOTES: Padres OF Will Venable missed his second straight start with a sore lower back, similar to the injury that landed him on the DL earlier this season. ... San Diego RHP Chris Young is scheduled to make his fourth start of the season Wednesday night, his third since returning from a five-month stay on the DL. The Cubs' scheduled starter is Randy Wells. ... Dempster struck out nine for the fifth time this season. He became the third Canadian-born pitcher with at least three 15-win seasons. The others are Fergie Jenkins (10) and Russ Ford (3). ... The Cubs, fifth in the NL Central, improved to 16-8 in September.