MIAMI, Oct. 10, (Ticker) -- Antoine Walker had a big debut for the Miami Heat, but it was Kevin Braswell who saved the day.

Walker scored 20 points and Braswell connected on a layup as time expired as the Heat posted a 103-101 triumph over the San Antonio Spurs in the preseason opener for both teams.

Video highlights from Spurs-Heat: Watch

One of several high-profile offseason acquisitions by the Heat, who were edged by the Detroit Pistons in Game 7 of the Eastern Conference finals last season, Walker connected on 9-of-14 shots and also had five steals.

However, it was Braswell -- who will be hard-pressed to earn a roster spot in Miami with point guard Jason Williams and Gary Payton ahead of him on the depth chart -- who got to play the hero. He drove down the left side of the lane a flipped in a left-handed shot to beat the buzzer.

The starters for both clubs played into the third quarter in what could be a preview of the NBA Finals. Dwyane Wade scored 18 points in 25 minutes and Shaquille O'Neal added 17 while playing 22 minutes for Miami.

Tim Duncan scored 16 points for the defending champions while Manu Ginobili and Brent Barry added 13 apiece.

San Antonio rookie forward Fabricio Oberto sprained his ankle in the contest. The 6-10 Argentine, who scored two points in 13 minutes, is expected to see significant time at small forward for the Spurs this season.