San Antonio Spurs will stay focused in NBA Finals, says Tim Duncan

Spurs went 3-1 ahead in the seven-match finals series with a 107-86 win on Thursday, meaning they now need just one more victory to seal a first title since 2007.

Duncan contributed 10 points and 10 rebounds in their most recent success, with the two teams set to lock horns again in San Antonio on Sunday.

And while the Spurs hold a healthy advantage, Duncan knows they must maintain their level of performance as the Heat will not relinquish their crown - which they have won for the last two seasons - without a fight.

"(It is a) great position for us, obviously going back home with a close out game," he said.

"(But) they're a very good ball club, obviously they're the champs and they're going to come out and they are going to show a lot of fire and come with a lot of energy.

"We're going to use our home court and we're going to come with that same focus that we did in these last two games and hopefully close it out at home."