Lakers Get Knocked for a Loop : Pro basketball: Playoff hopes wane after 112-104 collapse against Portland gives Nuggets 4 1/2-game edge for final berth.

This was no Coop-a-loop, the high-flying basketball shows from days gone by. This was Michael Cooper’s new gig, temporary as it was, being turned into a flat tire.

His coaching debut, serving as the interim to the interim while Coach Magic Johnson was in Michigan for his high school all-star game, looked great early. But the Lakers and Cooper went under in the second half, dragged down by scoring 39 points and shooting 36.4% to eventually lose to the Portland Trail Blazers, 112-104, before 12,888 at Memorial Coliseum and fall 4 1/2 games behind Denver with eight games left.

“Usually in a year you have four seasons,” Cooper said. “It seems like we had a good summer season. We played well in the first half and we had a lead. But we went from summer to winter real quick.”

That winter was also the Lakers’ fall, when they trailed only 89-85 with 8:59 remaining and then fell off the pace. Five turnovers in eight possessions tends to do that.

“We played a big game last night, and that took a lot out of us emotionally,” said Tony Smith, who led the Lakers with 18 points. “Tonight, we played well the first half and knew they would make a second-half run at us. It was just a matter of whether we could withstand it. We couldn’t.”

So Cooper is 0-1 and waiting for his next chance, even if that’s not what the pinch-hitting assignment was all about.

“I think this is like anything,” he said. “I’m just taking over for Earvin, who had a prior engagement. Why I was chosen, I don’t know. But we’ll see.”

If this was, in fact, a chance for Cooper to get his feet wet with an eye toward the future, he got a handful after the Lakers’ loss to Denver on Friday at the Forum in the biggest game of the season. They were down, and Cooper knew it.

“You can see it,” he said before the game.

Come tipoff, though, you couldn’t see it. When the Trail Blazers went 3:08 without a field goal, a stand that made defensive specialist Cooper proud, the Lakers converted a stretch of that into a 9-0 run and a 48-37 lead. The cushion stayed around 11 points much of the rest of the second quarter, peaking at 12 at 60-48, before Portland closed to 65-56 at halftime.

Within 3:44 of the second half, the entire lead was gone, having been turned into a 69-67 advantage for the Trail Blazers after a 13-2 rally. Cooper had already called two timeouts in the quarter, one a 20-second. That helped stopped the bleeding before the Lakers got down by more than three points in the third period.

Laker Notes

Nick Van Exel on Friday became only the fifth Los Angeles Laker to score 1,000 points as a rookie, joining impressive company: Jerry West, Magic Johnson, Norm Nixon and James Worthy. West holds the record for first-year players, at 1,389 points. Van Exel can’t catch him, but went into the Trail Blazer game needing only 32 points in the final nine outings to pass Worthy and 107 to pass Nixon for No. 3. “I haven’t really thought about it much,” he said. The record Van Exel does have his eye on is the NBA mark for three-pointers by a rookie. He began the night second to Orlando’s Dennis Scott, needing 15 to pass. . . . Kurt Rambis missed his second game in a row because of a strained rib muscle. . . . Michael Cooper becomes the fourth person to coach the Lakers this season, following Randy Pfund, Bill Bertka and Magic Johnson.

Western Conference Playoff Race

How the Lakers stand in their bid for the eighth and final playoff berth in the Western Conference.

Team W L GB GR Seattle* 56 18 8 Houston* 53 20 9 San Antonio* 52 23 7 Phoenix* 49 25 8 Utah* 47 28 7 Portland* 45 30 7 Golden State 43 31 8 Denver 37 36 9 Lakers 33 41 4 1/2 8