The Cubs are in a bit of a rut — the rare kind for them that produces positive results.

Strong starting pitching, solid defense, clutch hitting and yet another grand slam contributed to extending their season-long winning streak to five games Friday.

Matt Garza earned his first win since July 12 of last season, going seven strong innings in the 7-2 triumph over the Diamondbacks at Wrigley Field.

And for the second day in a row, a grand slam propelled the offense. Outfielder Scott Hairston had the distinction Friday after pitcher Travis Wood cleared the bases against the White Sox on Thursday.

"That's how you score," manager Dale Sveum said. "All of our runs were on homers."

In addition to Hairston's big blast in the third inning that gave the Cubs a 6-0 lead, Alfonso Soriano had a two-run homer in the first and Cody Ransom a solo shot in the third.

Soriano was walked intentionally to give Hairston the opportunity for his third career slam.

"Nobody likes to see that when you are on deck and they (intentionally) walk to get to you," Hairston said. "But given the situation (with runners on second and third and one out), hey, I don't blame manager (Kirk Gibson) for doing it. That's probably what I would have done.

"But I wasn't managing. I was playing. So I had a job to do, regardless of what I was thinking. I just wanted to realize the situation, put together a good at-bat and get the runner at third home any way I can. I was able to connect on one."

Garza, who opened the season on the disabled list with a shoulder injury, threw 93 pitches in his third appearance of the season, giving up two runs on six hits and striking out four.