CHICAGO -- September is when the Giants define themselves.
San Francisco tends to hone its knack for winning World Series in even-numbered years during the calendar's ninth month. It's when a decent ballclub becomes a formidable one and competent performers scrape the ceiling of greatness.
The Giants enter September with a seemingly pedestrian 72-60 mark. They trailed the first-place Dodgers by 1 1/2 games in the National League West. However, the Giants owned similar or identical records at the same juncture in each of their championship campaigns: They were 72-60 in 2010, 74-58 in '12 and 70-62 in '14. They surged to 20-10 finishes in '10 and '12, and an 18-12 conclusion in '14.
Various Giants have excelled on the September stage. Consider 2010, when Tim Lincecum (5-1, 1.94 ERA) and Jonathan Sánchez (4-1, 1.01 ERA) were utterly dominant. Or '12, when Barry Zito personally went 5-0 to finish a stretch in which San Francisco won his final 11 regular-season starts. Then there was '14, when shortstop Brandon Crawford hit .365 after beginning September with a .225 average.
Manager Bruce Bochy awaits more sustained excellence from his pressure-tested Giants. It could come from catcher Buster Posey, the 2012 NL Most Valuable Player who's batting .353 in his last 25 games. Or the source could be center fielder Denard Span, who's on a .400 binge.
The new month begins for the Giants in challenging and fitting fashion, with a four-game series against the Chicago Cubs. It's challenging, given the Cubs' status as baseball's premier team. It's fitting, because Chicago exposed the Giants' weaknesses last season by sweeping them at Wrigley Field Aug. 6-9. San Francisco can prove that it's primed for better days with a strong showing against the Cubs.
The schedule also provides the potential for a dramatic finish, since the Giants and Dodgers will clash in six of the final 13 games.
The Giants can't afford to experience another prolonged skid. They went 9-25 from the end of the All-Star break through Aug. 24, earning them the dubious distinction of posting the Major Leagues' worst record through that period after finishing the first half with the best record in the bigs.
That collapse also knocked San Francisco out of first place on Aug. 16, after it had maintained at least a share of the division lead since May 11. The Giants can take comfort in their current perch atop the league's Wild Card standings.
Crawford, the NL's reigning Gold Glove and Silver Slugger winner at his position, expressed confidence that the Giants can persevere enough to return to the postseason.
"We have a clubhouse full of guys that have been through tough times before and been a World Series-winning team," he said.
Though pitching, hitting and defense distinguished the Giants' efforts at different times during their peak years, it's an intangible quality -- selflessness -- that's at the heart of their success. This trait survives within this year's squad. Jake Peavy never complained about being dropped from the starting rotation. Starters and relievers alike never have complained about how Bochy uses them or when they're removed. All-Star first baseman Brandon Belt handled being replaced by Posey as the team's No. 3 hitter with dignity. Trade Deadline acquisition Eduardo Núñez, another All-Star, has calmly accepted his migration throughout the batting order.
A former Giant, Pittsburgh right-hander Ryan Vogelsong, recently described the character conducive to winning that Bochy nurtures.
"I thought that's why our teams won at the end of the season all the time," Vogelsong said, "because we had guys who were willing to sacrifice themselves and it didn't matter who got the headlines for getting the big hit. It was just about winning the game."
The road ahead
Manager Bruce Bochy's squad is striving to sustain its even-numbered-year excellence after winning the World Series in 2010, '12 and '14. Madison Bumgarner was enough to carry the Giants to the title in '14, but they'll likely need more help this time.

• Home games: 13
• Road games: 17
• Games vs. teams over .500: 14

• Two key series: Sept. 1-4 at Cubs; Sept. 19-21 at Dodgers

• Help on the way? Matt Cain (back strain) is likely to rejoin the rotation at some juncture. Outfielders Grégor Blanco (right shoulder) and Mac Williamson (left shoulder) should add depth if and when they heal.

• Cause for concern: Recent malaise lasted so long and was so all-encompassing that (a) San Francisco can ill-afford another slump, and (b) the Giants can't be considered truly strong in any phase of the game.