CHICAGO -- On a windy day at Wrigley Field, the fortunes finally blew in the Chicago Cubs' favor.
"It's a big relief," Cubs manager Dale Sveum said. "It shows you sometimes how tough it is to win a major league baseball game."
The Cubs' skid was their worst since they opened the 1997 season with 14 straight losses.
"I think now everybody is more relaxed," Soriano said. "Now we have to keep doing our jobs and win some games."
"We have to turn it around. You have to believe in this team because we're not that bad."
The gusts were blowing out at 35 mph on a 90-degree afternoon and the ball was flying. There were eight home runs, including four by each team and two from San Diego's Chase Headley, and a total of 17 extra-base hits.
Chicago trailed 7-6 in the sixth inning when Soriano launched a drive off Alex Hinshaw (0-1) over the right-field bleachers onto Waveland Avenue.
"We haven't had a game like that in a while where we have a lot of guys break out and get multiple hits, driving the ball," said Stewart. "Losing that many in a row was getting old."
Stewart also had a big day in the field, cutting down the potential game-tying run in the seventh when he threw out Headley trying to score on a grounder to third.
"I take a lot of pride in my defense, so whenever I can make a play out there, it makes me feel good," he said.
Everth Cabrera and Will Venable connected for San Diego, which lost its fourth in a row. The Padres hadn't hit more than two home runs in a game all season and came into the game last in the majors with only 18 overall.
Headley had four hits, including a double.
"Right off the bat, I think you knew it was going to be an offensive game," Padres manager Bud Black said. "It was good see a number of guys swing the bats, get multiple hits. Hopefully, that can carry over -- not only tomorrow but moving through the week."
Randy Wells (1-1) picked up the win in relief.
Barney hit a solo shot in the second and Stewart's two-run shot capped a three-run fourth that put the Cubs ahead 6-4.
Castro hit an 0-2 pitch onto Waveland to pad the one-run lead in the seventh.
Headley hit a tying homer leading off the fourth, then tied it again with a two-run drive in the fifth.
It was Headley's second multihomer game of the year. He has seven home runs this season after hitting just four in 113 games in 2011.
"When it's hot and you come here and the wind's blowing, you're going to be rewarded for good swings," Headley said. "When the conditions are like that, you know you have to put up a good amount of runs to be able to win the game."
Carlos Quentin hit an RBI double in his Padres' debut to give San Diego a 1-0 lead and snap their streak of 26 scoreless innings.
Quentin was activated from the 15-day disabled list prior to the game. He had arthroscopic surgery on his right knee in March after being acquired from the Chicago White Sox on Dec. 31.
DeJesus got the Cubs going in the first with a leadoff triple and scoring on Castro's single. Castro stole second and later scored on Bryan LaHair's groundout.
Cubs starter Travis Wood lasted just five innings. He was tagged for a season-high six runs on seven hits, including four home runs.
San Diego starter Jeff Suppan yielded six runs over five innings.
Game notes Cabrera's solo shot in the fourth was his first homer since July 11, 2010. ... The Padres optioned OF Blake Tekotte to Triple-A Tucson to make room on the roster for Quentin. ... San Diego OF Cameron Maybin (sprained right wrist) missed his second straight game after leaving in the sixth inning Saturday. He remains day-to-day. ... Padres RHP Huston Street (right shoulder strain) felt "really good" after throwing off a mound Sunday, Black said. He is scheduled to throw another bullpen on Wednesday. ... The Cubs activated RHP Carlos Marmol from the 15-day DL and optioned RHP Rafael Dolis to Triple-A Iowa. ... Jeff Samardzija (4-3, 3.00 ERA) will pitch for the Cubs on Tuesday against San Diego's Eric Stults (1-0, 1.96).