San Francisco @ Chicago preview

Last Meeting ( Jun 28, 2011 ) San Francisco 6, Chi. Cubs 3

THE STORY: The National League West-leading San Francisco Giants are surging. With Tim Lincecum seemingly rounding back into form, it doesn’t appear they will slow down any time soon.

Coming off his first win in nearly a month, Lincecum looks to help the Giants extend their season-high seven-game winning streak Wednesday against the host Chicago Cubs. San Francisco has outscored opponents 34-16 during the winning streak. The Cubs, meanwhile, have lost eight of 11.

TV: 8:05 pm. ET, Comcast Sports Bay Area, WGN (Chicago)

PITCHING MATCHUP: Giants RH Tim Lincecum (6-6, 3.16 ERA) vs. Cubs RH Ryan Dempster (5-6, 5.31).

Lincecum won for the first time in five starts on Thursday when he struck out 12 in seven outstanding innings against Minnesota. “The Freak” hadn’t been his usual self prior to that, entering the game with the highest ERA in June (7.59). He had issued 12 walks in his previous three starts, but walked only two against the Twins. The two-time Cy Young Award winner is 3-3 with a 3.50 ERA in seven starts against Chicago (he’s 2-0, with a 1.69 ERA in three starts at Wrigley Field). Blake DeWitt (6-for-15) is the only Cubs’ hitter to enjoy success against Lincecum.

Dempster is winless in his last three starts despite a 2.46 ERA in that stretch. The righthander allowed four runs – two earned – and nine hits in six innings of Friday’s 6-4 win over Kansas City. He is 5-8 with a 4.65 ERA in 24 appearances against San Francisco.

ABOUT THE CUBS (32-48): In a continuation of a stunningly bad start, the Cubs have lost 18 of 27 games this month. A quick glimpse at pitching stats explains the main reason for their struggles. Chicago entered Tuesday’s doubleheader with the worst team ERA in baseball (4.68). The biggest reason for future optimism on the North Side is the continued maturation of shortstop Starlin Castro, who had his career-best 11-game hitting streak snapped after going 0-for-5 in the opener of the doubleheader. The 21-year-old, whose 106 hits rank third in the majors, is batting .396 (21-for-53) over the last 13 games. Aside from Castro, both Aramis Ramirez and Carlos Pena are red hot, having each hit three homers in the last two games.

ABOUT THE GIANTS (46-34): The Giants have been winning with pitching. Which is why it’s surprising that Tuesday’s doubleheader sweep was powered by the offense. San Francisco, which entered last in the majors in runs scored (265), totaled 19 runs and 30 hits. Pat Burrell and Aaron Rowand each had three RBIs as the Giants set a season-high in hits (18) and runs in a 13-7 series opening win. Even struggling veteran Miguel Tejada contributed, hitting his first home run since April 8. The Giants are now 27-6 when scoring more than four runs

FINAL PITCH: Eighty percent of the Giants’ games have been decided by three runs or less (64 of 80) – the highest mark in the majors.