The second-seeded Spurs lost Game 2 at home, giving away home-court advantage to the pesky SuperSonics. They also lost center David Robinson, who remained in San Antonio receiving treatment for a sore back.
Robinson's absence moved Duncan into the center slot and the superstar responded by making nine of 17 shots and nine of 11 free throws, adding five blocked shots and four assists. He was too much for the smaller Sonics, who repeatedly double-teamed him to no avail.
"Our double-teams at times didn't get there," Sonics coach Nate McMillan said. "At times, we were slow."
After briefly sputtering at the start, the Spurs raced to a 57-39 halftime lead. Much of it was Duncan's doing as he collected 17 points, nine rebounds and four assists.
Parker made 10 of 15 shots as he established a season high. He scored 13 points in the opening period before burying Seattle in the third quarter. The rookie from France scored eight points in a 10-2 run that widened the lead to 77-52 with a minute to go.
"I just try to be aggressive," Parker said. "David is not here, so somebody else has to step up."
"What he did and who he did it against -- it was a tight game, he was making those moves and handling the pressure at 19," Spurs forward Malik Rose said. "I was a college kid with some acne at age 19."
Duncan and Parker led a stellar effort by San Antonio, which shot 53 percent, including seven of 11 from three-point range. It committed just eight turnovers while holding Seattle to 36 percent shooting.
"Most of the time, we were taking the ball out of the net where we had to set up and play a half-court game," McMillan said. "When a team forces us to play pretty much the whole game in a half-court setting, we have trouble."
Antonio Daniels scored 15 points and Rose added 14 and nine for the Spurs, who can wrap up the series Wednesday night. The three days off can only help improve the condition of Robinson's back.
"Elimination games are the hardest games of the whole year," Rose said. "They don't want to go home losing two on their home court. It's going to be really, really physical. There will be some elbows, some pushes, maybe even some punches. But we're going to keep our head because we have a bigger picture in mind of where we want to be."
Gary Payton scored 20 points but was the only Seattle player with more than 10. The Sonics got next to nothing from their frontcourt and were outscored, 48-28, in the paint.
Seattle also has injury problems. Forward Rashard Lewis suffered a shoulder injury and left in the third quarter. Lewis, who missed the last 10 games of the season with a sprained ankle, scored just six points.
San Antonio missed six of its first seven shots and trailed, 11-2. But the Spurs regrouped behind Parker to take a 23-21 lead after one period.
"The crowd was crazy and I just said to myself, `I've got to try and do something,'" Parker said. "I'm going to try and penetrate and get some easy baskets. You just try to play physical. Hey, that's playoff basketball."
"Rook (Parker) was attacking great and getting into the middle and finding people for open shots and making some shots himself," Duncan said. "We knew that when we got down that we had to grind it out. Luckily some shots started falling. We turned our `D' up a little bit and got some stops and got back into the game."
LGBT community has 'bullied the American people': Bachmann
Attkisson leaves CBS News, reportedly over network's 'liberal bias'