Kawhi Leonard admitted a tough start to the third quarter proved costly for the Toronto Raptors as the Golden State Warriors levelled the NBA Finals.

Toronto led 59-54 at half-time on Sunday but an 18-0 run for Golden State straight after the break turned Game 2 around, with the reigning champions eventually triumphing 109-104.

Leonard finished with 34 points and 14 rebounds but could not help the Raptors stretch their winning run in the playoffs to six games, a sequence that included their four straight victories over the Milwaukee Bucks in the Eastern Conference Finals.

"I feel like in that third quarter we didn't score the ball in the first five minutes, maybe four and a half minutes. That obviously led to them getting out in transition early and a lot of layups and open looks. That was pretty much the game right there," the three-time All-Star told the media.

"They went on like an 18-0 run, I believe. You can't do that with a championship team on the other side.

"I felt like our pace was good early, it was just that third quarter that really killed us. [An] 18-0 run, we can't score no baskets, you're not going to win no game."

Toronto produced a late rally, cutting the gap to 106-104, but Andre Iguodala's three-pointer in the closing seconds ended their comeback hopes.

The series sits at 1-1 as it switches to Oracle Arena in Oakland, California, with Game 3 on Wednesday.

Asked about the key to winning on the road, Leonard replied: "Just coming in as one. Obviously on somebody else's home floor they've got the sixth man with the crowd.

"We just have to buy into ourselves, come out hard. No mistakes, no turnovers. Just the same thing you've got to do at home."

The Warriors will hope to have Kevon Looney and Klay Thompson available after they picked up chest and hamstring injuries respectively on Sunday, with the latter set to undergo an MRI scan on Monday.

Golden State have not had Kevin Durant available yet in the series, though Leonard insists they are a tough team to beat no matter who is playing for them.

"We've still got to go out and make shots and guard guys who are out there," he added. "Obviously they are missing Durant and it’s a big loss for them, but they won the game tonight."