ABC’s “Jimmy Kimmel Live” got off to a promising ratings start in its new, earlier timeslot Tuesday, beating out David Letterman and holding its own against Jay Leno.

ABC was doing fine in latenight but believes the time is right for the 45-year-old Kimmel to plant his flag on the turf that has been the domain of Leno and Letterman, both of whom are in their 60s now.

Kimmel has been a slow and steady ratings gainer in recent years and is coming off his most watched quarter to date to close out 2012 (1.94 million), according to Nielsen. Still, he’s not expected to consistently outdraw the timeslot veterans — at least at the outset.

On opening night, with Jennifer Aniston and musical guest No Doubt, “JKL” averaged 3.10 million viewers from 11:35 p.m. to 12:35 a.m., its second largest audience ever and nearly 60% better than its prior season average when it started at midnight (1.94 million). In the same hour, NBC’s “Tonight Show with Jay Leno” averaged 3.27 million, and CBS’ “Late Show with David Letterman” drew 2.88 million.

In adults 18-49, “Tonight Show” averaged a timeslot-leading 1.08 million, with “Jimmy Kimmel Live” (887,000) well ahead of “Late Show” (683,000).

Kimmel ranked No. 1 in the demo in 13 of the 25 markets with Nielsen People Meters: New York, Chicago, Philadelphia, Dallas, San Francisco, Atlanta, Houston, Seattle, Miami, Cleveland, Orlando, Sacramento and Baltimore.

In its first outing at 12:35 a.m., ABC’s “Nightline” averaged 1.72 million viewers; head to head for the half-hour, it outdrew NBC’s “Late Night with Jimmy Fallon” (1.50 million) and CBS’ “Late Late Show with Craig Ferguson” (1.42 million). The NBC program won in both adults 18-49 and 25-54.

“Nightline” was averaging nearly 3.9 million same-night viewers this season, and it figures to take auds time to get used to its new, later timeslot.