The Oklahoma City Thunder may be packed with young players, but what they lack in experience they appear to make up for in maturity.

The Thunder, who have an average age of 26.4, earned their fourth straight victory on Wednesday with a Game Six win over the San Antonio Spurs to advance to the NBA Finals for the first time since moving from Seattle, 107-99.

After trailing by 18 points in the second period, the Thunder came roaring back, lead by Kevin Durant and Russell Westbrook, to outscore the Spurs 59-36 in the second-half.

 This is the toughest game I've played since I've been here, Durant said. But we kept playing hard. I tried to inspire my teammates with my play on both ends of the floor, and I'm glad we got this victory for Oklahoma City.

Durant was nothing short of spectacular. He finished the game with 34 points and 14 rebounds, while playing the entire 48 minutes.

It's an amazing moment for him to play like this in this moment, in this setting, and I wasn't going to take him out, Thunder head coach Scott Brooks said. I don't care how many times he looked at me fatigued. He has enough, and I think all of our guys have enough to play. You just have to fight through it.

San Antonio jumped out to big early lead, and looked like the same squad that won 20-straight games.

Led by their savvy veteran players, Tim Duncan, 36, Manu Ginobli, 34, and Tony Parker, 30, the Spurs scorched Oklahoma City in the first-half, and made it seem as if this series was heading back to San Antonio for a decisive Game Seven.

Parker alone had 21 points and 10 assists in the first half.

Yet despite their ignited play, their momentum would not last long.

After a rather lackluster second quarter, the Thunder started the third quarter with energy and determination.  Oklahoma City went on an 11-2 run early in the third period, and eventually took the lead going into the fourth.

The coaches said we got to play with force, with a sense of urgency and we didn't want to go back to San Antonio, Durant said. Leave everything out on the floor.

The Spurs simply had no answer for the Thunder.

They were more energetic, said Ginobli. They played better defense, they were more aggressive.

Of course, we can't have their legs, their energy. We're never going to jump as high or run as fast.

Game One of the NBA Finals will be played on Tuesday night in Oklahoma City against the winner of the Eastern Conference Finals.

The Boston Celtics hold the series lead at 3-2.