Iverson, Sixth Man Award winner Aaron McKie and starters George Lynch and Eric Snow all sat out to recover from offseason surgery. Last season, Philadelphia played through numerous injuries to reach the NBA Finals for the first time in 18 years.
Led by Dirk Nowitzki, who scored 16 points, the Mavericks got off to a quick start and opened a 44-17 lead midway through the second quarter. The Sixers battled back within 65-60 entering the final period and still trailed by five when Brown was thrown out.
With 4:41 left, Brown argued a flagrant foul call against Sixers forward Michael Smith and was ejected. Smith also was thrown out and the four ensuing free throws gave Dallas an 83-74 lead.
Tim Hardaway scored 13 points and Steve Nash added 12 for the Mavs, who made the playoffs last season for the first time since 1990. Hardaway was acquired from Miami to back up Nash at point guard.
Raja Bell and newcomer Matt Harpring each scored 21 points for Philadelphia. Harpring and fellow forwards Cedric Henderson and Robert Traylor were acquired from Cleveland for forwards Tyrone Hill and Jumaine Jones in the offseason.