SACRAMENTO, Calif. -- Kevin Durant and the Oklahoma City Thunder are no longer just a young team happy to make the playoffs, they are convinced they are legitimate NBA championship contenders this season.
"We're growing up, We hold ourselves to a higher standard now," said Durant, who leads the NBA in scoring this season.
It was another strong effort for Durant, who had nine of his 32 points in the fourth quarter against Sacramento in Oklahoma City's 120-112 win over the Kings on Monday night.
Russell Westbrook had 30 points and nine assists for the Thunder, who beat the Kings for their fifth straight victory.
Oklahoma City (55-26) has clinched the Northwest Division and will be seeded no worse than fourth in the playoffs. The Thunder trail Dallas by a game and the Los Angeles Lakers by a half game.
The Thunder, who had an emotional road win Sunday against the Los Angeles Lakers, are 16-3 since losing to the Memphis Grizzlies on March 7.
They conclude their regular season Wednesday at home against the Milwaukee Bucks, while Dallas meets New Orleans.
Despite the strong finish over the past six weeks, Durant said it won't mean much once the playoffs begin this weekend.
"It's very important (how we finish), but we also know that what we did in March and April is all out the door once the playoffs start," said Durant, who made four free throws in the final 41 seconds to secure the victory.
The Thunder will head into the playoffs with Kendrick Perkins handling the middle. Since arriving in a trade with Boston on Feb. 24, he has brought a toughness and defensive presence to a team that lacked it a year ago.
"I see this team really starting to play together," said Perkins, who had six points, three rebounds and blocked two shots.
"We're starting to think defense first. We keep improving and we have a bunch of guys who are hungry. They like to win and take losing hard."
Despite a dismal record and a possible move to Anaheim looming, the Kings (24-57) played inspired before a boisterous crowd of 15,683 that at times showed its verbal support by chanting to keep the team in Sacramento.
"(The move) is not something I'm thinking about, I'm a Sacramento King," said Cousins, whose free throws made and attempted were both records for a rookie in the Sacramento era. "The only thing I'm thinking about Wednesday is finishing this season with a bang. Like I said, I'm a Sacramento King."
Serge Ibaka, who moved into the starting lineup when Jeff Green went to Boston, had 14 points, eight rebounds and six blocks for the Thunder, who trailed by six points at the half.
James Harden scored 10 of his 12 points in the fourth quarter when the Thunder converted 16 of 17 free throws to hold off the Kings.
"It was great to come in here and get a win on the road in back-to-back games," Thunder coach Scott Brooks said. "This is not an easy place to play. They have been playing good basketball. We knew that we were going to be in a good game tonight."
If the Thunder win and the Mavericks lose, Oklahoma City moves into the third slot because it defeated Dallas 2-0 in the season series. The Lakers have two games remaining, including the season finale in Sacramento.
"The Lakers was a big win, but it was even bigger to come in here tonight and keep it going," said Westbrook, who added six rebounds, two steals and a block.
"We're ready to go once the playoffs start. We're older and know what to expect this year."
The Kings quickly opened a 10-point lead early in a high-scoring third quarter that was both physical and fast paced.
Scoreless in the opening half, Ibaka scored 12 points in the third and Westbrook had 11. Durant's 3-pointer just before the buzzer gave the Thunder an 87-83 lead.
The Thunder went on a 7-1 run to open the fourth and built the lead to 101-89 by the 8:55 mark. Inspired by their fans, the Kings kept the game within reach.
The Kings cut the lead to 114-110 on Thornton's 3-pointer, but Westbrook answered with a jumper with 55 seconds left to put the Thunder ahead by six.
The Kings played without last year's rookie of the year, Tyreke Evans, who sprained his left ankle in Sunday's victory over the Golden State Warriors. Evans said he would play against the Lakers.
The Kings are 11-29 at home and must defeat the Lakers on Wednesday night to avoid tying the worst home record in franchise history. The Kings went 11-30 in 2008-09. ... Thunder backup center Nazr Mohammed made all five shots and had 10 points, five rebounds and five fouls in 18 minutes.