Michael Beasley, the second overall draft pick in June, had 21 points for the Heat, but missed a chance to force a second overtime when the second of his two free throws rattled out in the closing seconds.
"The game started off a little slow for us. We had a lot of turnovers getting used to this new offense," Harris said. "It took a while to get a little warmed up to what we needed to do out there. In the second half we did a bit better at hitting the outside shots and that opened up the lanes."
Dwyane Wade also scored 21 points for Miami and was largely rested in the third and fourth quarters, while Vince Carter was limited to only eight points for the Nets before limping off after tweaking his left hamstring.
"The severity of it we don't know. We'll just go day by day and see how if feels," Nets coach Lawrence Frank said. "But that gave an opportunity to see Chris Douglas-Roberts and his scoring practically held us together."
Douglas-Roberts had 18 points and helped the Nets rally.
The Heat led 41-29 in the second quarter, but the Nets rallied to take an 87-77 lead with less than 5 minutes left in regulation. Miami fought back before Stromile Swift's dunk put the Nets ahead 91-89 with 30 seconds remaining. Miami's Daequan Cook scored to send the game to overtime.
"For the most part it was an enjoyable game," Wade said. "The young guys didn't give up and continued to play. I think it's a good thing. They've got to know how to make plays and keep their composure."
Wade thinks Beasley's pressure miss will help him learn when he faces the same situation in bigger games.
"No question it will, he's a competitive guy and has immense talent and skill," Wade said. "Sometimes it goes in and sometimes it doesn't. I think he understands that another day is another play. Don't get your head down."
The Heat will play the Nets again Sunday in London, part of the annual NBA Europe Live tour. Also, the New Orleans Hornets will face the Washington Wizards in Berlin on Tuesday, and three days later in Barcelona, Spain.
"I think it's great the NBA comes here, the players get energized by it," Frank said. "The crowd was so energized and to be in such a beautiful city makes it a fun game."
Carter hopes to recover in time to play on Sunday.
"It feels OK, it was more like a tweak," Carter said. "I think I landed funny, but I was able to catch it before I did anything bad to it. I just want to be cautious and try and work my way into the line up on Sunday if I can."
Wade and Carter drew huge cheers from the crowd of 15,000. So did Miami's Yakhouba Diawara, who grew up in the Paris suburbs.
"I was very happy to come back home, I only played one time before in this stadium," he said.
Both teams are looking to rebound from disappointing seasons. The Nets failed to make the playoffs for the first time since 2001 last season, and the Heat were an NBA-worst 15-67 in 2007-08.
"This is an extended training camp for us," first-year Heat coach Erik Spoelstra said. "Any additional playing time for us is good."