Just about the only person not surprised about Carlos Silva’s unblemished record is Silva himself. After going 5-18 with a 6.81 ERA in two frightful seasons for the Seattle Mariners, Silva is 5-0 with the Cubs. His latest victory came Tuesday night, when he gave up Todd Helton’s first home run of the season but otherwise pitched six splendid innings in the Cubs 6-2 victory against the Colorado Rockies.Ryan Theriot‘s two-run single capped a three-run eighth inning that broke open the game.Even with Silva, the Cubs are a disappointing 18-22, but they take a three-game winning streak into a road trip that starts Wednesday at Philadelphia. Lou Piniella said he had no idea what to expect from Silva, who came to the Cubs from Seattle in December in the Milton Bradley trade. The Mariners wanted to get rid of the 31-year-old right-hander so badly they paid the Cubs to take him.He got nice support Tuesday from three rookies as the Cubs won a series for only the fourth time this year. Tyler Colvin had three hits, Starlin Castro drove in two runs and James Russell pitched an impressive inning of relief.Silva took a five-hit shutout and a 3-0 lead into the seventh. Then he issued his only walk — to Troy Tulowitzki — and made his only mistake: a 3-2 fastball that Helton deposited into the right-field bleachers.It was the first home run since Sept. 30 for Helton, once one of baseball’s most feared power hitters.Helton, who has nine RBI this season, averaged 35 home runs and 118 RBI in his first seven full years with the Rockies but only 15 and 73 over the past five years.Silva departed after the home run and reliever Esmailin Caridad walked Miguel Olivo on four pitches. Russell came on to retire the side on two strikeouts and a pop-up.Then came the Cubs three-run eighth off Rafael Betancourt. Colvin singled, Soto walked, Castro singled to make it 4-2 and Theriot had his two-run hit.Rockies starter Jhoulys Chacin (2-2) allowed three runs on five hits and five walks in 5 2/3 innings. After pitching 14 1/3 scoreless innings in winning his first two starts, the 22-year-old rookie has given up nine runs over 10 2/3 innings in two losses.Colvin, Castro and Kosuke Fukudome drove in the fourth-inning runs.

NOTES—Silva also won his first five decisions in 2004. He became the first Cub to start 5-0 since Greg Maddux in 2006 and the first starter to begin his Cub career with five victories since Mark Clark in 1997 on a team that started that year 0-14….Castro’s RBI’s were his first since he drove in six runs in his May 7 big-league debut…..Olivo,formerly of the White Sox, left the game in the seventh after landing face-first in the dirt while stealing second base. Manager Jim Tracy said Olivo complained of a sore neck…..Rockies CF Carlos Gonzalez extended his hitting streak to 12 games.