Dream Debut Very Nearly a Nightmare : Basketball: U.S. trails surprising Spain at one point in first half before pulling away for a 115-100 victory.

Here’s another difference between these squads.

The Dream Team warmed up in Monaco amid the casinos and topless sunbathers on the Riviera.

Son of Dream Team opened Thursday night in a half-empty arena in this blue-collar city on the shore of Lake Ontario.

Amid suitably threadbare surroundings, the U.S. began play in the World Cup with a lackluster 115-100 victory over unheralded Spain, which is not expected to play in the medal round. If there had been a spread, the Americans would have missed it by 29 points.

That was the average margin of victory of the Dream Team at the 1992 Olympics, 44 points. No opponent scored more than 85 on the Americans at Barcelona and none ever led as late as Spain did Thursday when it went up, 42-41, with 5:27 left in the first half.

The Dream Team’s smallest margin of victory was 32 points, over Croatia in the finals.

The Dream Team also never had a player unhappy over playing time or a coach who suggested he couldn’t get through to his players, but Son of Dream Team had both: a gloomy Dominique Wilkins and a frazzled Don Nelson.

“We have many great individual players,” Nelson said. “We have to learn to play as a team.

“That’s not an easy lesson to learn. You can talk ‘til you’re blue in the face but they have to experience it and see for themselves. It doesn’t happen in two weeks.”

Nelson started Reggie Miller at forward in a three-guard lineup, hoping to knock Spain off balance with quickness, but it never happened. The day may have passed when clumsy Europeans struggled to bring the ball up against greyhound American guards or maybe Nelson’s players weren’t into it, but the Spaniards sneered at their pressure.

The Americans, warned over and over they have to guard everyone on the perimeter in the international game with its three-point line at 20-feet-7--three feet shorter than the NBA--had to experience that for themselves, too.

In the first half, a 7-footer named Ferran Martinez scored 10 points while Shaquille O’Neal and Alonzo Mourning guarded the lane. In one stretch, Spain scored on 16 of 19 possessions.

“Just the whole flow of European basketball kind of threw us for a loss,” starting point guard Kevin Johnson said.

“We couldn’t get a read defensively. Big guys normally have a tendency to help out in the paint, but you can’t leave their big guys because they shoot that college three-pointer like they’re free throws.

“Normally when you have guard penetration, the other guard helps out, which is what you’ve been told to do your whole life. They kick it out to a guy shooting a three-pointer.”

In the second half, Nelson actually told his players not to press as hard and finally American depth told, if not in the earth-flattening style of you-know-whom two years ago.

The U.S. went up by 23, then nodded off once more and Spain closed within 15 at the end.

“I’m disappointed,” said Miller, who scored 21 points. “This is a great wake-up call for us. This is something we definitely needed. Everybody has been patting us on the back and catering to us. Hopefully we’ll pick up the papers tomorrow and get something else.”

They’ll get more than that. They’ll see their first hint of ego conflict, manifested by Wilkins, trying to suck it up but plainly unhappy after being kept out until the last seven minutes.

This was better than Steve Smith, who didn’t get in until the last five.

Nelson noted he couldn’t play everybody--and added he was going by the merit system.

“We have to look back to our training camp,” Nelson said, “and decide who were our best players there. Those 10 players were basically playing better there.

“I’m planning on basically staying with this rotation. I like this rotation very much. It’s not that they (Wilkins and Smith) won’t be part of it because they will be, but they’re going to be in more of a reserve role.”

Said Wilkins: “Of course, it’d be hard for me if I don’t play. You know, I’ve paid my dues in this league. I deserve the right to be here and the right to play. But if that’s his decision, hey, no problem, I’m cool.”

Aside from that, it was another totally dominating night in international basketball for the U.S. pros.

“We had a 20-point lead,” said Nelson, trailing assurances in his wake. “I think we could have won handily if I would have kept the pressure on and left the starters in the game. I chose not to do that and I think it’s a good lesson for us to learn.”

Basketball Notes

In Thursday’s other Pool A game, China made 12 of 15 free throws in overtime to beat Brazil, 97-93. . . . In Pool B, Croatia beat Cuba, 85-65, as Dino Radja of the Boston Celtics had 25 points and eight rebounds. Croatia’s NBA frontline of Radja, Toni Kukoc of the Chicago Bulls and Stojan Vrankovic, formerly of the Celtics, finished with a 45-20 rebound advantage. Australia hung on to beat South Korea, 87-85, scoring only one point over the final six minutes as South Korea closed an 86-71 deficit to 86-85 with 55 seconds to play. Andrew Gaze, who finished with 31 points, made one free throw with 13 seconds left and South Korea missed a final three-pointer. . . . In Pool C, Russia beat Argentina, 84-64, as Yevgeni Kissourin had 19 points. Joey Vickery came off the bench to score 14 points in Canada’s 83-52 rout of Angola. . . . In Pool D, Jose Ortiz had 19 points to lead six scorers in double figures as Goodwill Games champion Puerto Rico cruised past Egypt, 102-74. Panagiotis Fassoulas had 18 points and 10 rebounds to lead Greece to a 68-58 victory over Germany.