MILWAUKEE — John Lackey, perhaps the man of the fewest words in the Cubs’ clubhouse, had a few for teammates before the series opener Thursday against the Brewers:

“This is not a small series, boys.”

Three 10-inning games and a pitching gem later, the Cubs had won three of four against the Brewers and headed to St. Louis looking for a National League Central clincher that could happen as soon as Tuesday.

If anyone doubted it before the series, veteran Ben Zobrist made it clear after a 5-0 victory Sunday at Miller Park.

“It’s the playoffs already for this team,” said Zobrist, whose two-run homer in the seventh inning helped back a three-hitter by Jose Quintana — the Cubs’ first shutout in more than a year. “We’re in postseason mode, and we intend to continue that for the next month.”

In the short term, they have their sights set on a celebration at Busch Stadium against the arch-rival Cardinals. A victory Monday would eliminate the Cardinals from the division race and drop the magic number to one for eliminating the Brewers, who are idle Monday.

“It will be nice to do it there. I’ll just say that,” said Zobrist, who related the big-series message from Lackey. “So we knew it was a big one here in Milwaukee, and it’ll be another big one in St. Louis.

“We intend to clinch there, and for a lot of guys that have been around here for a long time, it’s going to be very satisfying.”

It would be the Cubs’ first title clinch in St. Louis since 1938 (that one for the NL pennant).

“That would mean a lot,” said catcher Willson Contreras, who beat out an infield hit ahead of Zobrist’s homer — two weeks after returning from a hamstring injury. “Our team is really special, and we’re going to be ready for every game in St. Louis.”

The Cubs came from behind Thursday and Friday to beat the Brewers in extra innings before blowing leads in the ninth and 10th in a loss Saturday.

Sunday belonged to Quintana (7-3 with the Cubs), who struck out 10 and walked just one in his second career shutout. He nursed a 1-0 lead through six before Zobrist extended it.

“The thing I like is that we reacted in a playoff manner for these four games,” manager Joe Maddon said. “Our mental intensity could not be beat.”

Nobody seems to have had more playoff-race intensity than Quintana, the left-hander acquired from the White Sox during the All-Star break who has talked openly and emotionally about the chance to pitch in the playoffs for the first time.

On Sunday, he said his goal was to preserve the recently taxed bullpen, and he only seemed to get sharper as the game went on, needing just 13 pitches to get through the final two innings.

“It’s huge when you get that confidence [from the manager],” Quintana said of Maddon’s willingness to let him bat in the top of the ninth, knowing he’d get the ball in the bottom of the inning. “It’s special.”

Even playoff-like in September in Milwaukee?

“I think so,” Quintana said. “I don’t know because I haven’t been there. But this series was huge.”

Quintana is 2-0 with a 1.63 ERA in four starts in September, a stretch that began with a 1-0 team victory in Pittsburgh and a vow to be in the playoff rotation.

“Once he got over here, he was really jacked up about having a chance to play in the playoffs, and he’s showing you that,” Maddon said. “Games like that to me could be kind of career-altering for a pitcher. When you pitch a complete-game shutout on the road under these circumstances, that hopefully does something for your interior. It definitely fluffs it up a little bit.

“I’m curious as he continues to move forward from that game.”

Follow me on Twitter @GDubCub.

Email: gwittenmyer@suntimes.com

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