MIAMI — Ryan Dempster pitched seven crisp innings and the Cubs beat the Florida Marlins 2-0 on Friday night.Alfonso Soriano and Geovany Soto each hit an RBI double for the Cubs, who matched their season best with their fourth consecutive victory.Carlos Marmol worked out a jam in the ninth to earn his 32nd save in 37 chances, completing the five-hitter. Florida put two runners on with no outs before Marmol retired the next three batters, with shortstop Starlin Castro making a diving catch in short left field to rob Logan Morrison and end the game.Dempster (14-10) allowed three hits and walked three en route to his fifth consecutive road victory. He finished with 123 pitches.