The subject was money, specifically the amount of cash Roberto Duran would earn after winning the world welterweight championship from Sugar Ray Leonard Friday night.

Mike Trainer, Leonard's attorney and the man who put together the deals that created the most lucrative gate in the history of professional boxing, was smiling now, three hours after his man had lost his title.

"It's $1.5 million for Duran," he said. "That's the only thing we feel good about right now. As I said to myself last night, we can't lose."

The final figures will not be in until the middle of the week, Trainer said. But from preliminary reports, as many as 1.5 million fight fans paid their way into more than 300 North American closed-circuit television outlets, including a sellout at Capital Centre. At an average price of $20 per ticket, that translates into a $30 million take.

Leonard's cut from the live gate of 46,317 and the closed-circuit revenues was estimated by Trainer to be around $10 million.

"After this fight," Trainer said, "Ray doesn't ever have to fight again. If Ray decided to retire, but I'm not saying he's gonna, but if he decided not to fight, there would be no problem at all."

Duran did not get a dime from the closed-circuit broadcast, but simply a $1.5 million guarantee. If he and Leonard fight again, quite obviously he and his promoter, Don King, will get a far larger piece of the action.

That is exactly what King was saying today at a postfight press conference.

"It would be fine to have a rematch," King said, "on the same terms and conditions, reversed. Trainer was adament (on terms for Friday's fight) and Carlos Eleta (Duran's manager) is adament now. If Ray really wants the title badly, he'll do that. When you are the champion, you are the big draw and you're going to get the big money.

"Duran has been a superstar for 10 years, but he doesn't speak English. But he beat the darling of America . . . . Now, we go for the money."

Trainer said, "I think that he (King) is ludicrous. It shows why we never made a deal with him in the past. I wish Roberto Duran and Don King all the luck in the world, but I don't see this fight as adding to his (Duran's) attractiveness in any way. And I see Ray being more popular now after losing once than he was going in."

The Montreal promoter of the fight -- the Olympic Installations Board -- said it needed 41,000 in the stadium to break even.

The crowd exceeded that total by more than 6,000 and justified spending $5.5 million in taxpayer money by insisting the out-of-town fight crowd would pump as much as $20 million into the city's economy.

All 2,000 of the $500 tickets -- the most expensive seats in the house -- were sold out last week. The crowd might have exceeded 50,000 but for all-day rains and cool temperatures that probably kept several thousand more from watching in the wet. CAPTION: Picture, New welterweight champion Roberto Duran has currency in one hand and the head of promoter Don King in the other after receiving a $2,000 bonus from King. Duran also received $1.5 million tax free. UPI