Kevin Love had 22 points, 12 rebounds and five assists, and Ricky Rubio had an impressive debut with six assists, six points and five rebounds in 26 minutes for the Timberwolves, who hung with the Western Conference favorites all game long.
The Wolves led 96-95 with 3 minutes to play when Westbrook drove the length of the floor, hit a layup and the free throw for a three-point play to put the Thunder ahead.
Oklahoma City never trailed the rest of the way, but this one was in doubt from start to finish.
With new coach Rick Adelman on the bench and Rubio, Williams and JJ Barea added to the roster, there is a buzz surrounding the Timberwolves, who lost 132 games over the previous two seasons and haven't been to the playoffs since 2004, for the first time in ages.
The Wolves sold out their home opener for the first time since 2007, and there is a new hope coming from one of the league's most hapless franchises. Much of it centers around Rubio, the dazzling, 21-year-old point guard who arrived from Spain this offseason after being chosen fifth overall in 2009.
''I've been hearing about him for six years and I saw him for the first time 30 minutes (ago) and it was like he is real,'' Thunder coach Scott Brooks said before the game, with only a hint of sarcasm. ''Like a folk hero.''
Rubio entered with just over 3 minutes to play in the first quarter, and he electrified Minnesota's offense with his sensational passing. He zipped a pass through the lane that nearly took Thunder forward Nick Collison's head off before finding Barea for a layup. That started a run of three straight assists that got the crowd on its feet and gave the Wolves a 32-26 lead in the second quarter.
Oklahoma City knows all about expectations. The core of Durant, Westbrook and Harden has been together for three years now, and the Thunder are expected to challenge for the Western Conference crown this season.
After beating Orlando to open the season on Sunday night, the Thunder had a little trouble finding their shooting legs early. They missed 20 of their first 28 shots, and Durant started the game 2 for 8.
Westbrook was equally quiet early, but he finished the first half with a jaw-dropping flourish to help the Thunder take the lead. He scored on a layup, knocked down a jumper and then crossed Luke Ridnour over so severely at the end of the half that the veteran point guard fell to the ground on a drive that gave Oklahoma City a 52-46 lead at the break.
The Thunder looked to be pulling away in the third when they opened up a 12-point lead, but the young Timberwolves hung around.
Love hit a free throw and scored on a putback and Rubio's pullup jumper gave them that 96-95 lead. But Beasley forced a jumper and then had a chance to tie the game in the closing seconds, but Kendrick Perkins played good defense and closed the door on his drive.