The loss will likely only delay the celebration for Indiana (48-28), which hasn't won a division crown since 2003-04 and has only four division titles in the franchise's NBA history.
The Pacers also could have wrapped up the division with a Chicago loss Friday, but the Bulls held on for an 87-86 win over Orlando.
So Indiana will get its next chance to win a division title without Reggie Miller on Saturday at Washington.
But the loss could prove more costly in the overall picture. New York's 101-83 win over Milwaukee leaves the Pacers 1½ games behind the Knicks in the chase for the No. 2 seed in the East.
"Our goal above all else was to win the division, so we have to regroup tonight, prepare tomorrow for Washington which has been playing tough at home and go out and try to clinch this thing," West said.
For the first three quarters, the game lived up to its billing between two of the NBA's top teams.
Durant changed everything in the fourth quarter.
He scored the first six points in a 9-0 run, turning a 72-67 lead after three quarters into an 81-67 cushion early in the fourth. And when it looked as if the Pacers might rally midway through the fourth, Durant closed off that charge, too, with back-to-back 18-footers and a 3-pointer that made it 88-74 with 4:37 to go.
Indiana never challenged again in a game that featured 12 lead changes and 10 ties in the first half.
"We've matured as a team," Westbrook said. "We're doing a good job of playing together at the right time. Mentally, we wanted to come out and play the right way. It was important for us to come out and be aggressive. We didn't want to wait around and see how they were going to play."
Notes: Indiana will not play another team from the West unless it reaches the NBA Finals. ... Oklahoma City won both games against Indiana this season. ... The Pacers have won five straight games three times this season but have yet to win six in a row. ... The Thunder, the NBA's top free-throw shooting team, were 19 of 23 from the line.