Oklahoma City battled the Miami Heat tooth and nail for the first four games of the NBA Finals, but in Thursday's crucial Game Five the young Thunder were outgunned, losing 121-106 to surrender the championship series 4-1.

"It hurts. It hurts, man," said 23-year-old Kevin Durant, the Thunder's three-times NBA scoring champion who scored 32 points on Thursday. "We're all brothers on this team, and it just hurts to go out like this."

Thunder coach Scott Brooks said he was proud of his team, which features two 23-year-olds and a 22-year-old, center Serge Ibaka, among the starting five.

"I just told the guys, we didn't win a championship this year, but they gave it a championship effort all season long," Brooks said.

"It's something I'm proud of. I love our guys. I love what they're about. They're winners.

"Unfortunately we didn't accomplish our goal of winning the championship but I thought we gave great effort all year long to put us in this position."

The first four games all came down to the final minutes, with Miami and LeBron James finding a way to grind out three successive victories after Oklahoma City won the opener.

There was little drama in the final game, however, as the Heat led 31-26 after the first quarter, extended their lead to 10 by intermission and then used a blitz of 16 points in a row in the third quarter to open up a massive 25-point lead.

"We made it to the finals, which was cool for us, but we didn't want to just make it there. Unfortunately we lost, so it's tough," said Durant.

Russell Westbrook, who scored 19 points, as did NBA Sixth Man of the Year James Harden, another 22-year-old, said the Thunder's three top scorers stood together toward the end of the game and vowed to do better.

"We hugged each other and told each other to embrace this feeling and remember this feeling," said the 23-year-old.

"We've got to be the guys that come back and push everybody next season and just got to get better."

Harden said he believed the Thunder were moving towards an NBA title.

"My rookie year, making the playoffs. Last year, making the Western Conference finals, and this year making the finals. We definitely showed signs of improvement," said Harden.

"We're not too far away."

(Editing by Peter Rutherford)