James Harden is going to need much more help from his Houston Rockets teammates if he hopes to knock off the team that traded him away before the season started.

Kevin Durant scored 24 points, Russell Westbrook made a run at a triple-double in three quarters and the Oklahoma City Thunder routed Harden and the Rockets 120-91 on Sunday night in Game 1 of their first-round playoff series.

"Believe it or not, I think this was good for us," Harden said. "Losing like this was definitely good for us. Now we know how to play."

Harden scored 20 but Houston was held 15 points below its regular-season average while shooting 36 percent. The Rockets, who set a franchise record for 3-pointers during the regular season, finished 8 for 36 (22 percent) from behind the arc.

Harden didn't get much help from the rest of his fellow starters, who combined for a total of three career playoff starts, all by center Omer Asik. None of the other starters scored in double figures and the unit went 17 for 50 from the field, with Harden making just six of his 19 attempts.

"We really don't have an excuse any more," said Jeremy Lin, one of three Houston starters making their first career playoff appearance. "We played terrible all the way across the board - offensively, defensively. That one's over with."

The Rockets made the playoffs for the first time in four years after acquiring Harden in a surprising trade at the end of training camp. He went on to become an All-Star and finish fifth in the league in scoring.

"James, on this team, has to shoulder a ton of responsibilities for us and he's been great all year long," coach Kevin McHale said. "He's had an all-pro type of year ... He'll play better, just like everybody.

"We ask him to do an awful lot for us - handle the ball, score the ball, pass the ball, make plays. I think that he had it going there for a little bit, but it wasn't James. It was us in general as a team. We never really caught a flow at all tonight."

Game 2 is on Wednesday night in Oklahoma City.

Harden said he tried to block out what kind of reaction he might get from the crowd that once cheered for him and wore fake beards to mimic his trademark look. He was just focused on trying to win.

Hours before going head-to-head with Harden, Durant said that "we're not looking at him as a friend right now". But even right before tipoff, the situation didn't seem natural.

"It felt a little awkward just looking across there during the national anthem and seeing him with another team, but we've got to get past that. We're competing against his team, and he wants to win so bad," Durant said.