Fox’s eagerly anticipated premiere of its prehistoric adventure series “Terra Nova” went head-to-head against week two of CBS’s post-Charlie Sheen “Two and a Half Men” in a key ratings battle Monday night, and it was no contest, with CBS notching a big win, TVbytheNumbers.com reports.

The two-hour “Terra Nova,” a pricey Steven Spielberg production, pulled a 3.0 average overnight rating in adults 18-49, a number that the story says “has to be disappointing for Fox.” On CBS, meanwhile, episode two of the retooled “Two and a Half Men” was down from the premiere, as expected, but still posted a healthy 7.2 average in 18-49 — down 33% from a week ago — along with 20.03 million viewers.

It added up to a winning night for CBS overall, with much of its lineup coming close to premiere week results. “How I Met Your Mother” pulled in a 4.4 average in the 18-49 demo, off just 6%, while “Hawaii Five-0” scored a 3.3, down 3%. “2 Broke Girls” moved to its new time slot and fell 37%, but still notched a strong 4.5. And the season premiere of “Mike & Molly” had a series high at 4.9.

Over at ABC, “Dancing with the Stars” was off 18% from week one with a 3.3 in 18-49, and “Castle” settled for a 2.9, down 9%.

The news at NBC was all bad, with “The Sing-Off” falling to a series-low 1.7, down 11% from last week, and the much-hyped “The Playboy Club” suffering a 19% plunge to a mere 1.3 in adults 18-49 — establishing "Playboy Club" as a contender to become the first new show of fall 2011 to be canceled, the story says.