The pressure is on the Seattle SuperSonics.

The Sonics' NBA-best 63 regular-season victories won't mean anything unless they beat the Denver Nuggets in the fifth and deciding game of their first-round NBA playoff series. If they lose, they'll be out of the playoffs and in for a lot of second guessing."We have our work cut out for us," Sonics coach George Karl said.

The underdog Nuggets, who left Seattle trailing 2-0 a week ago, have a chance to make NBA history today when they seek to become the first No. 8 seed to beat a No. 1 seed.

"In Game 5, anything can happen," Dikembe Mutombo, Denver's 7-foot-2 center, said.

Actually, Seattle's 63-19 record does mean something. It means that the Sonics earned the homecourt advantage throughout the playoffs and, judging from the results at Denver in Games 3 and 4, they will need all the games they can play in the Seattle Coliseum if they're going to live up to their high expectations.

They began the season talking championship with the additions of Kendall Gill and Detlef Schrempf. Anything less would be a disappointment. A first-round defeat would be devastating.

On Thursday night, the Nuggets used two missed Shawn Kemp free throws with 45.3 seconds left in regulation to stay alive, then beat the Sonics 94-85 in overtime. On Monday night, Denver beat Seattle 110-93.

Reggie Williams scored 31 points for the Nuggets in Game 3. LaPhonso Ellis had 27 for Denver in Game 4.

"Now that we're down to a one-game series, anything can happen," Robert Pack of the Nuggets said.

The Nuggets don't have anything to lose. In the playoffs for the first time in five seasons, they're already proved they're a young team with a bright future.

The Sonics?

The Sonics are a team that entered the first round of the playoffs with a lot of questions despite their 63 victories: Did they have a go-to scorer to pull out a close game? Did they have enough perimeter shooting? Could they win in a halfcourt game? Could they overcome their poor regular-season free-throw shooting?

In Game 4, the Sonics led 82-79 when Kemp went to the free-throw line for two shots. Gary Payton came to the bench and told Nuggets' fans behind the scorers' table: "You aren't going nowhere."

Wrong!

Kemp missed both free-throw attempts, Pack hit a 3-pointer for Denver and the Nuggets wound up winning in overtime.

"We just threw the game away," Kemp said. "When you let a team hang around and you are struggling to shoot, anything can happen."

The Sonics still appear to be the team to beat. They won 37 of 41 regular-season games at home, then beat Denver 106-82 and 97-87 in the first two games of the playoffs.

Including the two playoff games, the Sonics are 4-0 against Denver at Seattle this season. They're 0-4 at McNichols Arena.

But this isn't the same Denver team that left Seattle last Saturday. It's a team with a new confidence, a club that is playing loose with nothing to lose.