-By Anthony Crupi

TNT on Tuesday tipped off the 2009-10 NBA season in championship form, drawing 3.68 million viewers with its opening night doubleheader.

At 7:30 p.m., the Celtics-Cavaliers game drew 4.02 million viewers, while the late Clippers-Lakers contest retained 83 percent of its lead-in, averaging 3.36 million viewers.

Taken together, the two games put up big demo deliveries, as TNT averaged 2.17 million viewers 18-49, up 35 percent from last year’s twin bill, while adults 25-54 were up 39 percent (1.91 million).

Male demos were up as well. TNT drew 1.56 million men 18-49, a 37 percent improvement over last year’s opening slate, while M25-54 grew 40 percent to 1.36 million.

All told, last night was TNT’s most-watched doubleheader since Feb. 2, 1996, per Nielsen live-plus-same-day data.