"It opens it up for me and Ray (Allen) when he's going to the basket strong like that and taking his time and finishing his shots or getting to the free-throw line," Lewis said about Wilcox.
The Sonics led by as many as 14 points early, but let Portland close the gap in the fourth quarter before pulling away with a 20-4 run.
Jamaal Magloire had 11 points and 12 rebounds for the Blazers, who have lost four straight and eight of their last 10 games. Portland was coming off a 116-111 overtime loss to the Lakers in which Kobe Bryant scored 65 points.
"The real problem was we have to play together. We can't just have three guys or just one individual carrying us. One individual doesn't get it for us," Blazers coach Nate McMillan said.
Seattle had its losing streak extended to five in a 99-98 loss to Golden State on Saturday.
"We knew what we had to do," Wilcox said. "We'd lost five straight games and most of them were in the fourth quarter."
Sonics coach Bob Hill joined Lewis in praising Wilcox.
"Chris was patient. He played a very mature post game, I'm really proud of him," Hill said. "He's aggressive and he's going to the rim."
The Sonics began to pull away from what had been a close game midway through the second quarter. Lewis hit a 3-pointer then added a layup and a free throw in the midst of a 12-0 Seattle run that made it 43-31.
The Sonics led by as many as 12 early and were up 47-37 at the half.
After the Sonics stretched it out again to 67-60 on Wilcox's jumper, the Blazers made another push -- getting to 67-66 on Dan Dickau's 3-pointer.
Portland could not get any closer than one and Lewis got a 3-pointer and a tip-in before Wilcox's layup and free throw made it 83-73 for Seattle.
Seattle outscored their Northwest Division rivals 28-16 in the fourth quarter.
"We finished the game in the fourth quarter," Lewis said. "We've given up a lot of games in the fourth quarter, we were able to keep the lead and win tonight."
Nick Collison had 16 points and 11 rebounds for the Sonics, who have won four straight at the Rose Garden.
Zach Randolph had 16 points and eight rebounds for the Blazers.
"It was not good, that's all," Randolph said.
Seattle guard Luke Ridnour started for the second game after missing five straight with a herniated disc in his neck. ... A 22-year-old fan, Evan Powell of Beaverton, Ore., earned the biggest cheer of the game by making a halfcourt shot to win a Toyota truck. ... Blazers coach Nate McMillan is 2-5 against the Sonics, a team he coached and played for to earn the nickname, Mr. Sonic. ... Portland hasn't lost four in a row since Dec. 29-Jan. 3. ... Seattle leads the series between the teams 2-1. The Sonics defeated Portland 97-73 at Key Arena last month. ... Both teams are 26-40 this season, tied for second-worst in the Western Conference.