Pre-season gamesThursdayCharlotte    105-92    ClevelandDetroit    99-98    MinnesotaSan Antonio    92-109    HoustonGolden State    74-90    PortlandMIAMI. The Miami Heat enter the 2013-14 NBA season as favorites to win a third consecutive title but with several teams sporting beefed up rosters the reigning champions face their biggest challenge to the crown yet.The Brooklyn Nets, Houston Rockets, Los Angeles Clippers and Golden State Warriors are among the teams that added key players in a bid to dethrone a Heat team that needed seven games to get by the aging San Antonio Spurs in last season’s final.But knocking a team led by All-Stars LeBron James, Dwyane Wade and Chris Bosh off its perch will be no easy feat given their desire to become the first NBA franchise to win three consecutive titles since the Los Angeles Lakers in 2002.The Nets, backed by Russian multi-billionaire owner Mikhail Prokhorov, sent a message that they are going all-in on winning a championship in June by acquiring future Hall of Famers Kevin Garnett and Paul Pierce as part of an eight-player trade with the Boston Celtics.But despite an upgraded lineup that features depth across the board, questions remain about how effective rookie head coach Jason Kidd, five months removed from playing in the NBA, will be on the sidelines.The Indiana Pacers put a scare into the Heat by forcing a seventh game in last season’s Eastern Conference Finals. Indiana wanted to make their bench better and they now boast one of the league’s best with the acquisition of C.J. Watson and the eventual return of Danny Granger from injury.The Chicago Bulls should be another contender in the East as Derrick Rose, the NBA’s 2011 most valuable player, returns after sitting out all of last season while rehabilitating an ACL that was torn in the previous campaign.The 25-year-old guard’s decision not to return late last season was the source of much debate in NBA circles but he can begin silencing any critics in his team’s season-opener versus the champion Heat on October 29.For the Heat’s part, they made a low-risk, high-reward move by signing big man Greg Oden, a former first overall draft pick who was expected to dominate the league but has since undergone multiple knee operations and not played in years.MOST DANGEROUSIn the West, the Los Angeles Clippers also tapped into the Celtics’ pool of talent by trading for head coach Doc Rivers, who won an NBA title with Boston in 2008, a move that enabled them to get a long-term deal from star point guard Chris Paul.Dwight Howard opted to leave the Los Angeles Lakers in his prime for less money to join a Houston team that is suddenly being considered a force in the West.The Rockets, who lost in the first round of last season’s playoffs, are hoping the 27-year-old center can rediscover the three-time Defensive Player of the Year form he had in Orlando and work with James Harden to shake up the West.Golden State also added their name to the list of contenders by signing free agent Andre Iguodala to round out a starting five lineup that is led by Stephen Curry and considered one of the most dangerous in the NBA.San Antonio, led by Tony Parker and Tim Duncan, re-signed Manu Ginobli and Tiago Splitter as they look to erase memories of last year’s Finals loss to Miami.The Spurs were so close to winning the title in Game Six that officials started bringing yellow tape out to block off the court for the Spurs’ trophy presentation but they squandered a five-point lead with 28 seconds left in regulation before losing in overtime and then falling in the decisive seventh game.The Oklahoma City Thunder should be better than they were in last season’s playoffs once star point guard Russell Westbrook returns from knee surgery, but they failed to make any moves to ensure they maintain their grip on the West.