The Cubs knew they were legit when they swept the Giants last year

11:54 AM ET

SAN FRANCISCO — Four days in August. They altered the 2015 season for the Chicago Cubs, taking their confidence to new heights. A sweep of the defending World Series champions will do that for a team, as the San Francisco Giants came to town the owners of three titles in the five past seasons. They left Chicago with the Cubs owning them. It was a sweep that changed everything for a young Cubs team.

“At that particular time it was in the middle of the summer,” pitcher Jon Lester recalled earlier this week. “It definitely had some wild-card ramifications for us where if we dropped three out of four it could put us in a pretty big hole. We end up sweeping them, so I think on a confidence level for some of the young guys that really helped.”

To review: The previous weekend, the Cubs had reached 10 games over .500 for the first time all season. It had been a grind to get there and, yes, they were feeling good about themselves. But they were far from a perfect team and what was to come in the fall was still a hope not a certainty. Still, things came together better that weekend than anyone could have imagined.

Hector Rondon celebrates getting the strikeout with the bases loaded for the save that sealed the sweep. Jon Durr/Getty Images

Game 1: Thursday, Aug. 6. Final: 5-4

The Cubs shot out to a 5-0 lead after two innings, thanks in part to Kyle Schwarber’s three-run blast in the second inning off Giants starter Chris Heston. But the win wouldn’t come easy as those were the last runs the Cubs would score, while starter Jason Hammel was surprisingly pulled by Joe Maddon after just four innings and a 5-2 lead. For the first time all season the Cubs manager showed a sense of playoff contending urgency.

“We took Jason out a little early that one game,” Maddon explained. “Paradigm shift.”

It was as if Maddon was telling his team a nice run to 10 games over .500 wasn’t enough. He wanted more — and he got it.

“Obviously, whenever you get the world champs coming in you want to elevate your game,” Hammel said. “When the best arrive you want to make sure your best is there for that game or series. It was a huge moment for us. A momentum builder. Almost a confirmation to ourselves that we were that good.”

At the time Hammel bristled at being taken out early but he was more than happy the Cubs held on as closer Hector Rondon sealed the deal with a one-two-three ninth inning.

Addison Russell’s move back to shortstop helped lead the Cubs’ charge. Brad Mangin/MLB Photos/Getty Images

Game 2: Friday, Aug. 7. Final: 7-3

The day before would mark Starlin Castro’s last game as the Cubs’ starting shortstop. His season-long slump had dropped his batting average to .236 after a 0-for-4 day. …

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