Bosh scored 21 points to help the Heat beat the Charlotte Bobcats 98-92 in a preseason game Tuesday night.
Bosh went 8 for 12 from the field with seven rebounds, five assists and two blocks in 25 minutes.
"It doesn't matter what position you're playing. It's playing big, playing athletic and playing long at your position, and he did that tonight," Spoelstra said. "He was a presence. He was aggressive to the rim. He was really our only threat consistently in the paint and at the rim, and he'll have to continue to provide that for us."
Bosh was coming off a six-point performance in Saturday's victory over San Antonio.
"It was just a good day," Bosh said. "I feel any time I'm aggressive, I can just be effective in some kind of way."
It was the Bobcats' first game in PNC Arena, about 2 1/2 hours northeast of Charlotte and home to North Carolina State of the Atlantic Coast Conference as well as the NHL's Carolina Hurricanes. The Bobcats also played New Orleans in Charleston, S.C., on Oct. 11 in an effort to expand their fan reach within the Carolinas.
Duke coach Mike Krzyzewski -- who has coached James, Wade and Bosh in the Olympics -- dropped by the Heat locker room to visit his former U.S. players afterward.
While the Bobcats were the home team, James and the reigning champion Heat certainly drew their share of cheers from the Raleigh fans -- many of whom crowded near the tunnel and even came down to the corner of the court seeking an autograph from James as he walked toward the locker room.
"It's fine," James said of the mob that gathered around him. "I think it's cool. The fans are really excited to get an opportunity to see us and their Bobcats. That was a very humbling experience just now with all the fans coming on the floor."
Miami led by 18 late in the third quarter before the Bobcats rallied to within 92-90 on Walker's layup with about 4 minutes left. But Charlotte couldn't tie the game or push ahead against the Miami reserves, including one possession when big man Bismack Biyombo missed a shot in the lane for the tie that led to a fast-break layup for Miami at the other end.
"I thought there was team chemistry," Bobcats coach Mike Dunlap said. "They felt like a team, they played like a team. It was a very good, solid game on both sides."