Grant Belcher, News9.com
DALLAS – It's tough to beat any team four times in a span of two weeks, much less the defending champs.
After two Thunder preseason victories and a regular season victory against the Mavs, Dallas finally bounced back with a 100-87 victory against OKC on Monday at the American Airlines Center.
It was the first loss of the season for the Thunder, who were one of only two remaining undefeated teams in the league entering the game. Oklahoma City fell to 5-1 while the Miami Heat also dropped a game to the Hawks on Monday.
The first quarter was classic Thunder-Mavs basketball with the game knotted at 20 at the first break.
But the Mavericks busted out of the gate in the second quarter, outscoring Oklahoma City with runs of 9-2 and 15-6 to get some breathing room.
In the third, a jumper from Kevin Durant cut the lead down to 56-51, but that would be as close as the Thunder would get for the rest of the game.
A quick 10-2 run from the Mavs broke the game open and Oklahoma City would not threaten again.
OKC was down a couple of players in the game as Daequan Cook sat with flu-like symptoms and Thabo Sefolosha left with right foot soreness early and did not return.
The rest of the OKC contributors played big minutes. Serge Ibaka played 41 minutes, Kevin Durant 39, Russell Westbrook 35 and Kendrick Perkins and James Harden both logged 31 minutes.
Durant led all scorers with 27 points, and Russell Westbrook had a nice game with 18 points, eight rebounds and three assists.
James Harden had 16 off the bench, and Ibaka was the other Thunder player in double figures with 10.
Dirk Nowitzki had 26 points to lead the Mavericks, who improved to just 2-4 so far this year.
The Thunder shot 40 percent in the game while allowing Dallas to shoot 49 percent.
The hectic schedule will continue as Monday night's game was the first in another five-games-in-seven-days span for OKC.
Oklahoma City will host the Portland Trail Blazers on Tuesday night at 7 p.m.