Cubs 8, Padres 6: Darwin Barney hit a two-run, walk-off home run to lift Chicago to a three-game sweep at Wrigley Field.
It is the Cubs' first sweep of three or more games since taking four at Pittsburgh from Aug. 1-4, 2011.
Chicago rallied in the eighth against former Cubs pitcher Andrew Cashner. Reed Johnson started it with a two-out single and pinch runner Tony Campana stole second and third. Campana scored when Starlin Castro slid into first base head first to beat out an infield single, tying it 6-6.
Bryan LaHair led off the ninth with a single against Dale Thayer (0-1) and Barney followed with a two-out blast to left-center on a 1-2 slider, his third of the season and the first walk-off homer of his career.
James Russell (2-0) pitched around two hits in the ninth for the win.
San Diego's Carlos Quentin went 3-for-4 with a pair of home runs and drove in four runs in his third game since making his season debut.
Chris Denorfia gave San Diego a 2-0 lead with a two-run home run in the second, his second of the season. Quentin followed with two-run blasts in the third and fifth.
Cubs catcher Steve Clevenger, who was activated from the disabled list Tuesday, went 2-for-4 with two RBIs in his first game since April 25.
Cubs starter Ryan Dempster allowed six runs in 4 1/3 innings. Dempster allowed three home runs after giving up only three in his previous eight starts.
Anthony Bass lasted only 4 2/3 innings in the start for San Diego, allowing five runs on six hits and four walks.
GAME NOTEBOOK: Quentin is 7-for-12 with three home runs and six RBIs since returning to the lineup on Monday. He had knee surgery March 19. … Cubs OF David DeJesus extended his hitting streak to nine games with a single in the fifth. … Castro extended his hitting streak to seven games with a single in the first. … Dempster is winless in 18 starts since Aug. 11, 2011.