Kawhi Leonard tallied a playoff career high 29 points as the San Antonio Spurs routed the Miami Heat 111-92 in game three of the NBA finals on Tuesday.

Tim Duncan finished with 14 points and six rebounds while Danny Green scored 15 points for the Spurs, who jumped out to a 25-point first half lead then held on for the victory and a 2-1 series lead.

The first half was an old-fashioned shootout as San Antonio put on the best shooting display for a half in NBA finals history, hitting 19 of their first 21 shots.

The two-time defending champion Heat cut the deficit to seven points at one stage in the second half but they never could recover from the Spurs' opening blitz that saw them shoot a superb 75.8 percent from the field to lead 71-50 at halftime.

LeBron James and Dwyane Wade pumped in 22 points each for the Heat, who suffered their first home loss of the 2014 post-season after winning eight straight playoff games at home going back to last season.

Game four of the best-of-seven series will be on Thursday night in Miami.