DEFENDING NBA champions the Dallas Mavericks are just one game away from clinching a play-off spot after their 117-110 victory over the Houston Rockets.The Mavs saw All-Star Dirk Nowitzki score 21 of his 35 points during a fourth-quarter rally as they inflicted a fifth-straight loss on the Rockets, who are in danger of sliding out of contention.Dallas can now wrap up a post-season place against the Golden State Warriors on Friday, their last home games of the regular season.The Boston Celtics all but wrapped up a 30th Eastern Conference Atlantic division title with a 102-98 win over the Orlando Magic.Paul Pierce had a career-high 19 assists, coupled with 29 points, to ensure the New York Knicks must win all their remaining four games just to tie with the Celtics.The Knicks were winners tonight as the in-form Carmelo Anthony landed 33 points to win 104-95 on their last-ever trip to New Jersey to meet the Brooklyn-bound Nets.The Chicago Bulls remain the top team in the Eastern Conference though as they routed an insipid Charlotte Bobcats 100-68 to move closer to the No.1 seeding.The Miami Heat are two-and-a-half games behind as they could afford to rest LeBron James in the fourth quarter after his 28 points sent them on course for a 96-72 win over the Toronto Raptors.The Philadelphia 76ers kept hold of a play-off place by beating the Cleveland Cavaliers 103-97 but the Milwaukee Bucks’ hopes were bruised by a 121-112 reverse against the Washington Wizards.The post-season picture became slightly clearer in the Western Conference, where the Memphis Grizzlies sealed their place by beating the New Orleans Hornets 103-91.The San Antonio Spurs held on to the top seeding as they smashed the Sacramento Kings 127-102 but the Oklahoma City Thunder remained just half a game behind as they won 109-97 at the Phoenix Suns.The Utah Jazz cashed in on the Suns’ loss to edge closer to a play-off place by beating the Portland Trail Blazers 112-91 while the Denver Nuggets are still hanging as the surging Los Angeles Clippers won 104-98.The Clippers are half a game behind city rivals and Pacific leaders the Los Angeles Lakers after they easily beat the Warriors 99-87.