NBC’s “Celebrity Circus” flipped ahead of the competition last night, barely. The reality series' debut built on its “Deal or No Deal” lead-in en route to winning its 10 p.m. timeslot, albeit against weak competition.

“Circus” averaged a 2.3 adults 18-49 rating from 9:30 to 11 p.m., according to Nielsen overnights. In the 10 p.m. hour, it finished 0.1 ahead of CBS timeslot competitor “CSI: NY,” which was a rerun.

The show got a boost from its lead-in, “Deal,” building on the show’s 2.1 rating from 8 to 9:30 p.m. In a good sign for NBC, “Circus’” rating held steady from start to finish, though it did decline in total viewers from 9:30 to 11.

“Circus” drew 6.3 million total viewers, nearly 3 million fewer than “CSI: NY.” Leading up to its premiere, the show, which features celebrities like Janet Evans and Christopher Knight, had been the butt of jokes for its absurd premise.

Last night also marked the series finale of “Men in Trees,” the ABC dramedy that was canceled last month following two years of low ratings. The show managed just a 1.1 rating for its ender, well below its season average.

Meanwhile, Fox led the night among viewers 18-49 with a 3.4 average rating and an 11 share. NBC was second at 2.2/7, CBS third at 1.7/5, Univision fourth at 1.6/5, ABC fifth at 1.4/4 and CW sixth at 0.6/2.
 
At 8 p.m. Fox was first with a 3.1 for “So You Think You Can Dance,” while NBC and Univision tied for second at 1.8, NBC for “Deal” and Univision for “Al Diablo con los Guapos.” ABC was fourth with a 1.4 for a repeat of “Wife Swap,” CBS fifth with a 1.2 for “The Price is Right” and CW sixth with a 0.5 for a repeat of “America’s Next Top Model.”
 
Fox led again at 9 p.m. with a 3.7 for another hour of “Dance,” followed by NBC with a 2.5 for the last half hour of “Deal” (2.7) and the first 30 minutes of “Circus” (2.3). CBS and Univision tied for third at 1.7, CBS for a repeat of “Criminal Minds” and Univision for “Fuego en la Sangre,” with ABC fifth with a 1.5 for a repeat of “Supernanny” and CW sixth with a 0.8 for “Farmer Wants a Wife.”
 
At 10 p.m. NBC took the lead with a 2.3 for the final hour of “Circus,” with CBS right behind with a 2.2 for a repeat of “CSI: NY.” Univision was third with a 1.4 for “Don Francisco Presenta” and ABC fourth with a 1.1 for “Trees.”
 
Fox also finished first for the night among households with a 5.4 average rating and a 9 share. CBS was second at 5.3/9, NBC third at 4.8/8, ABC fourth at 2.9/5, Univision fifth at 2.0/4 and CW sixth at 1.0/2.