The Chicago Bulls posted their third consecutive win on Monday, while the Los Angeles Lakers' woes continued with defeat in Philadelphia.
The Bulls enjoyed a 108-87 victory over the New Jersey Nets, but the victory was soured by a back injury suffered by superstar Derrick Rose, who could manage just over 10 minutes on court.
Rose is hopeful of being fit for Chicago's next assignment, against the New Orleans Hornets on Wednesday, and in his absence the Bulls were well led by Carlos Boozer with 24 points while Luol Deng scored 19.
The win improved Chicago's season record to 21-6 and kept them three wins clear of the Miami Heat on top of the Eastern Conference.
Things are not so rosy for the Los Angeles Lakers, who suffered their second loss in succession with a 95-90 defeat to the Philadelphia 76ers on the road.
Kobe Bryant scored 28 points for the Lakers, but a superb cameo from Louis Williams - who came off the bench to score 24 for the 76ers - was enough to get his team over the line.
Bryant's tally helped move him past his former team-mate Shaquille O'Neal into fifth place on the list of the NBA's all-time leading scorers.
Bryant's 28 points sees him on 28,601, ahead of O'Neal's 28,596, but still behind Wilt Chamberlain (31,419), Michael Jordan (32,292), Karl Malone (36,929) and Kareem Abdul-Jabbar (38,387).
The Oklahoma City Thunder continue to lead the Western Conference, bouncing back from their 107-96 loss to the San Antonio Spurs on Saturday with a 111-107 overtime win over the Portland Trail Blazers.
Kevin Durant scored 33 points for the Thunder, and Russell Westbrook added 28 as Oklahoma took their season mark to 19-5.
Chris Paul scored 29 points to help the Los Angeles Clippers stay in second place in the West with a 107-102 triumph over the Orlando Magic, and the Spurs held onto third spot by virtue of their 89-84 win against the Memphis Grizzlies, with Tony Parker scoring 21 points.
Elsewhere on Monday, the Washington Wizards enjoyed a rare success with a 111-108 win at home against the Toronto Raptors, the Knicks defeated the Utah Jazz 99-88 in New York and the Phoenix Suns ran out 99-90 victors over the Atlanta Hawks.
The Sacramento Kings were too good for the New Orleans Hornets on the road, winning 100-92, and the Houston Rockets accounted for the Denver Nuggets 99-90.