64!65!

He’s back. He’s way back. He’s back, back, back, back . . .

One day after conceding the historic home run race to Mark McGwire, slumping Sammy Sosa hit two balls Wednesday that screamed, “Just kidding.”

The first flew into the right-field corner, sailing over a dog track advertisement as Sosa sprinted around first base.

The second soared over the center-field fence and hit the bleachers so hard, the clang could be heard in Green Bay.

The ball bounced back to the grass, County Stadium shook, the Chicago Cubs danced, and Milwaukee Brewer center fielder Marquis Grissom had an idea.

He picked up the souvenir, looked around, shrugged, and stuck it in his pocket.

Nice try. If it were only that easy to capture what happened on another improbable day for baseball’s most improbable home run hero.

Sammy Sosa ended a 0-for-21 skid to hit his 64th and 65th homers of the season, tying him with Mark McGwire for the major league record and major league lead.

This, just before teammate Brant Brown dropped a fly ball with two out in the ninth inning for a three-run error that gave the Brewers a stunning 8-7 victory.

Same old Sammy, same old Cubs.

Sosa, who has been tied five times but never led in this chase, has three games remaining in Houston; McGwire has four games left against Montreal in St. Louis.

The Cubs must hope they can defeat the Astros while New York, which lost Wednesday to Montreal, 3-0, is losing in Atlanta.

Separate races, but apparently only one agenda.

“I still think [McGwire] will finish just ahead of me because I have another thing to think about, another thing to do, and that’s the playoffs,” Sosa said afterward. “I have to sacrifice myself to get on base while Mark, he can swing for the fences.”

Yet the only thing sacrificed here by Sosa on Wednesday was the Brewer pitching staff, one of the most undistinguished groups in recent history.

In coming years when critics of the home run chase blame it on expansion-year pitching, they will point to Sosa’s 12 homers against the following nine Milwaukee unfortunates:

Cal Eldred. Bronswell Patrick. Jeff Juden (since traded). Scott Karl. Bill Pulsipher. Valerio De Los Santos. Eric Plunk. Rafael Roque. Rod Henderson.

“This is my lucky team,” Sosa said with a smile. “How else can I explain it to you?”

On Wednesday it was Roque and Henderson’s turns, two rookies who obviously were scared to challenge him until forced.

In the first inning, Roque walked him on six pitches. In the third inning, Roque walked him on five pitches.

In the fifth inning, Roque threw him a ball outside, and the 45,338 fans began chanting, “Sam-my, Sam-my, Sam-my” and Roque became flustered and . . . here it came. A fat fastball in the strike zone.

Instead of trying to pull it down the left-field line and out of the building, Sosa had grown patient from the walks, and he waited. And waited.

When he finally swung, the ball was nearly behind him, but his sheer arm strength drove it into the right-field seats.

“Hitting the ball to right field, that surprised me,” teammate Gary Gaetti said. “He just overpowered it, just mashed it.”

Less than 30 minutes later, Sosa was really dropping jaws after battling Henderson during a seven-pitch plate appearance.

“I fought during that at-bat,” Sosa said. “But finally, I got the fastball, and I hit it.”

That’s it? Just like that?

You can be scuffling and muttering and conceding one night, and swinging your way into a tie for major league history less than 24 hours later? It’s that easy?

“Hey, I was struggling, I come back today, I felt great today, that’s part of the game, buddy,” Sosa said with a laugh.

At least the Brewer pitchers have served as equal opportunity batting tees.

Roque also gave up McGwire’s 64th homer last weekend. And Henderson gave up what should have been McGwire’s 66th homer before it was incorrectly ruled a ground-rule double by umpire Bob Davidson.

So the race goes on, four days remaining, a thousand things that can happen.

“It is amazing, isn’t it?” said Gaetti, who has played with Sosa and McGwire this season. “I can’t call it, man. Because the minute you say something. . . .

“Maybe they are destined to share the record. They both say they believe in God. Maybe he will see to it that they share it forever.”

Sosa was so impressive, when he came to the plate in the eighth inning for a shot at a third home run Wednesday, construction workers on the new stadium behind the outfield fence stopped to watch.

From about 800 feet away.

Who knows, they probably thought they had a chance to catch something.

Then, for a second consecutive day, he was surrounded by fans who ran out of the stands to worship at his feet.

“You can hardly put it into words,” Cub Manager Jim Riggleman said.

He was speaking of the slugger, but he could have been talking about the game.

If the Cubs lose the wild card to the Mets, they will look no further than Wednesday’s devastating ending for the reason.

“Nobody ever said this was going to be easy,” said Mark Grace, who doubled over at first base after Brown’s error. “My goodness, it sure isn’t.”

In the seventh inning, Steve Trachsel was throwing a two-hit shutout and the Cubs were leading, 7-0. Then he gave up two singles, a walk, a double, a sacrifice fly, another single.

And only then did Riggleman, fretting over his poor middle relief, finally take out the exhausted pitcher.

The Brewers finished the inning with four runs, added another in the eighth, then loaded the bases with two out against always-scary reliever Rod Beck in the ninth.

Rookie Geoff Jenkins of USC lofted a fly ball for what should have been the third out. But Brown, who entered the game an inning earlier as a defensive replacement, circled under it, had it hit the heel of his glove, squeezed too soon and dropped it.

“There were no shadows, no sun, no wind,” Brown said. “It was just a clink.”

All three runs scored, and now nobody in town is cheering harder for a weekend rally than he is.

“The bottom line is, basically, it’s a nightmare,” he said softly. “You hope you can wake up, but you know you’re not.”

A nightmare for some Chicago Cubs, a dream for others, sometimes both on the same afternoon, one long weekend left for everyone to figure out which is which.

* McGWIRE AT BAT: He fails to take lead back against Randy Johnson. C4