Red-hot Thunder clinch playoff berth, Celtics blast Heat Sun Apr 1, 2012 7:21pm EDT (Reuters) - The Oklahoma City Thunder made a major statement heading into the final month of the National Basketball Association (NBA) season with a playoff-clinching 92-78 home victory over the league-leading Chicago Bulls on Sunday. The Thunder (40-12) have enjoyed victories over the Miami Heat and Los Angeles Lakers as part of a six-game winning streak that strengthened their hold on the Western Conference and made their case for being the NBA's top team. "We came out with good energy and toughness and I thought it was important that we do that in this game," Thunder coach Scott Brooks told reporters. We played our best defense this year. The Heat (37-14), looking to get a late-season tune-up ahead of the playoffs where they will attempt to avenge last season's loss in the NBA Finals, suffered a setback in an eyebrow-raising 91-72 loss to the Boston Celtics. Boston's Rajon Rondo had a triple-double with 16 points, 14 assists, and 11 rebounds and Paul Pierce added 23 points as the Celtics handed visiting Miami their third loss in five games to keep them 3-1/2 games behind Chicago in the Eastern Conference. LeBron James scored a team-high 23 points for Miami but it could not mask an out-of-sync Heat offense as they shot just 34 percent for the day. Boston (30-22) went for the kill in the third quarter where they outscored their opponent 31-12 en route to extending their Atlantic Division edge to one game over the Philadelphia 76ers. The Thunder lead the West by three games. Their latest win saw them build a 30-point second-half lead over a Bulls team without Derrick Rose for a 10th consecutive game and showing signs of missing the NBA's reigning Most Valuable Player. Russell Westbrook scored 27 points and Kevin Durant added 26 points and 10 rebounds for Oklahoma City, who buried Chicago by outscoring them 31-12 in the third quarter. The Bulls (42-12) have held their own this season without Rose, who is still out with a groin injury, and are 14-6 when he does not play. But they have lost two of their last four games and their lead atop the league has been cut to one game over the red-hot Thunder. Writing by Jahmal Corner in Los Angeles; Editing by Frank Pingue