James Corden's tenure as host of CBS' Late Late Show got off to a solid start on Monday night.

Fast affiliate returns give the series 1.66 million viewers and a 0.4 rating among adults 18-49 — that's up 22 percent from the comparable showing last year with Craig Ferguson but flat in the key demo. Still, the adults 18-49 showing is improved 33 percent from Ferguson's average last fall before his December exit.

Among metered market ratings, the show scored a 1.4. That's up 17 percent from the series' season-to-date average, which has seen a slew of guest hosts pinch-hit following Ferguson's departure. It's also up 27 percent from the same night last year. Though not indicative of much, aside from awareness of the change, Corden also managed to beat direct 12:35 a.m. competition Seth Meyers by 17 percent. (Compared to Ferguson's more publicized launch back in 2005, Corden was off four-tenths of a point.)

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In the 25 markets with Local People Meters, preliminary stats on adults 18-49 give the advantage to Meyers. He outrated Corden by a tenth of a point, with a 0.5 rating compared to a 0.4.

Corden has been poised for slow-burn status since he was set as Craig Ferguson's heir six months ago. Though he's a household name in his native U.K., American audiences have had little exposure to the multihyphenate. And his March launchpad also sits months ahead of the big marketing initiatives behind David Letterman's Late Show sign-off and Stephen Colbert's debut in the fall.

One promotional tool CBS does have in its pocket right now is March Madness. The broadcast network's run of the NCAA basketball tournament, which has seen boosted ratings this year, kicked off last week. But, because of the schedules, it also means that Corden's first week on the air is an abbreviated one. Late Late telecasts only air Monday through Wednesday this week.

NBC's and CBS' after-hours options have always been relatively evenly matched among total viewers, though Meyers has maintained Jimmy Fallon's advantage since taking over Late Night last year. The demo is another matter. CBS' Late Late Show has trailed all of the notable late-night talkers among adults 18-49 for the last year, including TBS' little-watched Conan.

Season-to-date, Meyers has averaged 1.56 million viewers, 640,000 of them adults 18-49, over Late Late's 1.4 million viewers and 432,000 adults 18-49.

It's also worth noting that the late-night race has become increasingly reliant on how hosts can translate quick takes from their telecasts into viral moments that make the rounds the next day. (See the Jimmys, Kimmel and Fallon, and their YouTube empires.) No 12:35 a.m. show is going to set the ratings on fire, so Corden's ability to be a part of the next-day conversation will play a big role in measuring his success.