Chicago, IL (Sports Network) - Alfonso Soriano hit a two-run homer and drove in three as the Chicago Cubs held on to defeat the Colorado Rockies, 5-4, in the third of a four-game series at Wrigley Field.

Geovany Soto chipped in with a pair of doubles and a run batted in for the Cubs, who have won six straight games. The Cubs improved to 35-21, which is the best record in baseball. The last time Chicago entered the month of June with the best record was in 1908, which was also the last time the franchise won a World Series title.

"I'm not getting caught up in that," Cubs manager Lou Piniella said about the team's record. "It's still too early. We need to continue to play good baseball. We have something like 22 of our next 32 games on the road, starting Monday. So we need to keep our focus on winning."

Ryan Dempster (7-2) earned the win by going five frames and allowing three runs on three hits, while striking out seven and walking four. The right- hander has yet to lose at Wrigley Field this season. Carlos Marmol earned his third save of the season.

Omar Quintanilla had a two-run homer, while Todd Helton and Scott Podsednik hit solo shots for Colorado, which has dropped six in a row and nine of its last 11 games.

Glendon Rusch (1-3) was shaky over 4 2/3 innings in taking the loss. The veteran southpaw, who was making his first start with the Rockies, gave up five runs on nine hits, while striking out four and walking one. He took the rotation spot of Jorge De La Rosa, who has been shifted to the bullpen following a string of poor performances.

Rusch, who pitched three seasons for the Cubs from 2004-06, began this season with San Diego and went 1-2 with a 6.41 ERA in 12 relief appearances before being outrighted to Triple-A earlier this month. He refused the assignment and was granted free agency, then signed a minor-league contract with the Rockies on May 17.

Colorado jumped on Dempster for a pair of runs in the top of the second. Jeff Baker drew a one-out walk and Quintanilla followed by belting a two-run homer to right, giving the Rockies the early edge.

The lead was short-lived as the Cubs responded with three in the home half of the inning. Kosuke Fukudome got things started with a base hit and three batters later Dempster doubled to left, scoring Fukudome. Soriano then launched a two-run shot to right-center, putting Chicago ahead 3-2.

Soto's one-out run-scoring double in the third gave the Cubs a two-run lead.

Reed Johnson led off the Chicago fourth with a ground-rule double, moved to third on Dempster's sacrifice bunt and scored on Soriano's single to center.

Helton's solo homer to left in the fifth got Colorado within 5-3.

Neither team mounted much of a threat until the bottom of the eighth when the Cubs loaded the bases with two outs, but Derrek Lee struck out looking to end the frame.

Marmol was brought on for the top of the ninth and retired the first two batters, before surrendering a solo home run to Podsednik, but settled down to strike out Willy Taveras to end the game.

"You don't like to lose, but as long as you and your teammates play hard, you can deal with it," Helton said. "That's kind of the barometer of the team -- if you start to see guys starting to slack off and kind of giving up. You're definitely not going to get that here."