CHICAGO — Lou Piniella called upon decades of baseball knowledge when the Chicago Cubs were scuffling for the first two months. He watched intently, took mental notes and then started swapping out the parts.

Finally, he used some theatrics to literally kick-start his team. Turns out, a dirt-kicking temper tantrum against umpire Mark Wegner on June 2 was just what the Cubs needed, whether it was premeditated or not, whether it was the old Lou resurfacing in the more mellow one.

“It’s just evolved. I don’t think there were any turning points. We had to do some things to straighten ourselves out and just let the guys play,” Piniella said. “If things aren’t working — and they weren’t working earlier in the year — you try to do different things to shore things up.”

The Cubs fell nine games under .500 that day after Piniella was ejected, but are 61-42 since June 3. Now, 31⁄2 months later, Chicago is on the cusp of clinching the NL Central. The magic number is four headed into the final week of the season with three-game road series in Florida and Cincinnati beginning today.

The Cubs have a comfortable working margin, but the franchise has a long history of gut-wrenching collapses, like in 1969 when they led by 91⁄2 games in mid-August only to have the Mets whiz by them.

Three years ago, they led the wild card by 11⁄2 games with nine games left before falling apart in the final week, losing three of four at home to the Reds and missing the playoffs.

And four years ago, in Dusty Baker’s first season as manager, the Cubs led the Marlins 3-1 in the NL Championship Series. With a 3-0 lead in the eighth inning of Game 6, they were a mere five outs from the World Series. But Florida scored eight runs after a fan interfered with a foul ball, went on to win that night and again in Game 7.

So, nothing is safe. Not that the past means much to a team that was overhauled in the offseason with $300 million going to salaries.

The Cubs trailed Milwaukee this season by 81⁄2 games on June 23 but have caught and passed the young and talented Brewers.

“Nothing has been clinched yet,” said second baseman Mark DeRosa, one of the key offseason acquisitions. “Milwaukee, I have a lot of respect for them. They’ve played hard all year and we know they’re not going to go down easy.”

The season has been a memorable one already for the Cubs.

A franchise-record attendance of 3.25 million came to Wrigley Field. There was a fight in the dugout and clubhouse between ace Carlos Zambrano and catcher Michael Barrett, who was later traded; a brawl with the Padres; a $91 million contract extension for Zambrano, who criticized the fans for booing him and then later apologized. The temperamental right-hander has a career-high 17 wins but also 13 losses and has been bothered by heat cramping.

All this with the knowledge since opening day that the team is going to go on the auction block, probably sometime after the World Series.

The 64-year-old Piniella can’t name one specific game or incident he thinks got the Cubs turned around.

Still, making Ryan Theriot his every-day shortstop gave the team a spark, and the Cubs have never wavered in using their young players. Reliever Carlos Marmol has pitched 22 1-3 consecutive scoreless innings and catcher Geovany Soto, a late callup after an MVP season in the Pacific Coast League, has given the team another strong bat and good defense behind the plate.

Piniella mixed those young players with veterans like Alfonso Soriano, Aramis Ramirez and Derrek Lee. He moved Jacque Jones, who was languishing on the bench and nearly traded, into the starter’s role in center field and he also got a strong season from lefty starter Ted Lilly. All those have helped make the Cubs winners — they have 12 victories in their last 16 games headed into Tuesday night’s game at Florida.

“We’ve been preparing for this eventuality, for this last week,” Piniella said. “Now we’ve got business to take care of and hopefully we can do it soon so we can rest our team a little bit. But the important thing is getting it done, so we’re going to South Florida on Tuesday and go out and give it everything we got.”

For general manager Jim Hendry, it was Piniella’s leadership that kept the Cubs from getting into an even bigger hole.

“I thought Lou did a good job of weathering the storm and keeping everybody together,” Hendry said. “Lou didn’t panic. It’s not easy to play when you’re 8 or 9 games down. We were not far from being in a serious situation we couldn’t have gotten out of.”

Now they’re not far from the playoffs. The Cubs have only been to the postseason four times since their last World Series appearance in 1945. They haven’t won the World Series since 1908.

“We knew when we came out of spring training that we had the makings of a playoff-caliber team,” DeRosa said. “We didn’t get off on the right foot the way we would have liked to, but we found a hot streak at the right time and we’re getting it done.”