Oklahoma City, OK (SportsNetwork.com) - Tim Duncan scored seven of his 19 points in overtime, Boris Diaw led the way with 26 points off the bench and the San Antonio Spurs beat the Oklahoma City Thunder 112-107 in Game 6 on Saturday night to win the Western Conference championship. The Spurs became the first road team to win a game in the series and advanced to the NBA Finals for the sixth time in 17 years under coach Gregg Popovich. They've lost just once in that period, to LeBron James and the Miami Heat last year, when Miami walked away with its second straight title after taking Game 7 at home. The Spurs will have home-court advantage against the Heat this time, beginning with Game 1 on Thursday night. They sealed the deal without point guard Tony Parker, who was sidelined after halftime Saturday night because of a sore left ankle. Prior to Saturday, the home team had won each of the first five games in the series by an average of 20.4 points. The closest game had been the Thunder's nine-point win in Game 3. The Thunder, trying to make it back to the finals for the first time since falling to Miami in 2012, were led on Saturday by Russell Westbrook's 34 points, eight assists and six steals. Kevin Durant scored 31 with 14 rebounds, Reggie Jackson had 21 points and Serge Ibaka added 16 with four blocks.