Guard David Thompson broke loose for 35 points to carry Denver to a 123-114 victory over the Seattle Supersonics yesterday, keeping the Nuggets alive in their Western Conference championship series.

The Sonics now lead the series, 3-2 with the sixth game to the played Wednesday in Seattle and the seventh Friday in Denver, if necessary. Whichever team wins the series will host the Eastern Conference champion Washington Bullets Sunday for the first of seven scheduled games to decide the National Basketball Association champion.

Thompson, shackled through four games by Seattle's Dennis Johnson, scored 22 of his points in the second half, when Seattle staged a comeback that chopped a 19-point lead to five.

Thompson credited his point to better execution by the Nuggets, who are seeking to overcome history. Only two NBS teams have come back from 3-1 deficits to win a series. Denver won the series opener and then dropped three straight.

"We changed our offense a little bit," Thomspon explained. "We set some picks and they were getting me free for some jumpers. I haven't been getting the kind of shots I want to take. I'm a little tired and Dennis Johnson has been doing a good job on me."

Thompson hit 16 of 27 shots, most of them soft, looping jumpers from 15 to 18 feet over Seattle's defense, which was not as challenging as in the first four games of the series.

Denver nearly ran Seattle out of McNichols Arena in the first half.

The combination of a stout defense, which held Seattle to 44 points, a staggering 31-11 margin in rebounds and 16 points by center Dan Issel gave the Nuggets a 61-44 halftime lead.

Then came Seattle's comeback. It tightened its defense, improved its shot selection and shooting percentage (16 of 21 for 76 percent) and guard Gus Williams continued his personal spree.

Williams finished with 31 points on 15 goals in 25 attempts. And his shooting performance impressed Brown.

"Gus Williams hit some shots I haven't seen before," Brown said.

But then Thompson continued to find the range in the final quarter and Seattle became lodged in foul trouble.

Thompson mustered eight points as the Nuggets established a 13-point lead at 109-96 with 4:41 to play.

Meanwhile, Seattle lost Williamson and forward jack Sikma on fouls.

Then Denver withstood a desperate Seattle flurry which pared the spread to five, 113-108, with 2:21 to play.

Thompson followed with his final goal, guard Bobby Wilskerson sank two free throws and Issel added two more to clinch the victory with a 119-110 lead.

Thompson, who had been in a shooting in the series, studies film before yesterday's game and found that he was releasing his jump shot on the way up rather than at the apex. Buoyed by the return of his shooting touch he now feels the pressure in the series is on Seattle.

"There definitely is going to be pressure on them," he said. "If they don't win at home, they have to come back here and play. I don't think they will want to be placed in that situation. When it comes down to the last game anything can heppen. I definitely think we would have the advantage being at home."

That's all talk, Seattle guard Fred Brown.

"They are in the hole. They have two games, we have three games. In the queen's mathematics three is better than two. You have a better chance of getting to four from three than you do from two."