By Lynette Rice
Updated March 11, 2010 at 09:26 PM EST

It was a good first week back for Jay Leno. For the week ending March 5, The Tonight Show dominated in adults 18-49 and total viewers, outranking Late Show with David Letterman and ABC’s combination of Nightline and Jimmy Kimmel Live, according to final ratings released by NBC. For the week, Leno averaged 1.94 million adults in the 18-49 demo and 5.58 million total viewers; Letterman, in comparison, averaged 1.30 million adults and 3.66 million total viewers. Leno also outranked Letterman among adults 18-34.

Leno also gave a big boost to Late Night with Jimmy Fallon, which also out-delivered CBS’ Late Late Show with Craig Ferguson. Fallon attracted 916,000 adults in the 18-49 demo versus for 754,000 for Ferguson. He also beat his CBS rival in total viewers (1.949 million versus 1.802 million).

Before Leno’s return, Letterman was consistently dominating the 11:30 p.m. timeslot in viewers and occasionally among adults 18-49. Leno is already well ahead of what he was doing last season on The Tonight Show; he was averaging 5.1 million viewers before he left the franchise. Once Conan O’Brien took over in the fourth quarter, the show averaged 2.5 million.