Led by frosh hit “Undercover Boss,” CBS dominated primetime Sunday, winning all four hours in both the 18-49 demo and overall viewers.

CBS benefited by its March Madness NCAA men’s basketball tournament coverage running until approximately 7:30 p.m. on the East Coast, but the regularly scheduled primetime lineup still figures to hold its ground when the final scores come in from Nielsen.

According to preliminary nationals, “Boss” (4.6 rating/11 share in 18-49, 14.9 million viewers overall) was Sunday’s top-rated series. It created a nice leadin for “Cold Case” (3.9/11, 13.7 million) to win the final hour of the night.

An even bigger boost, from the NCAAs, helped lift “60 Minutes” (4.2/13, 16.1 million). “The Amazing Race” (3.5/9, 13.2 million) was the lowest-rated CBS show of the night but still had no trouble topping its competition.

No. 2 on Sunday in 18-49 was Fox, led by “Family Guy” (3.7/9, 7.3 million) at 9 p.m. “The Simpsons” (2.7/8, 5.7 million) and “The Cleveland Show” (2.7/7, 5.6 million) offered nearly identical numbers to each other to finish second in the demo in the 8 p.m. hour.

NBC’s highlights were some week-to-week improvement for “Minute to Win It” (1.9/5, 5.8 million) and the two-hour “Celebrity Apprentice” (2.8/7, 7.3 million) at 9 p.m. “Dateline: NBC” (0.9/3, 4.5 million) was almost even with Fox’s back-to-back reruns at 7 p.m. of the just-canceled “‘Til Death” (0.9/3, 2.5 million for the hour).

New Fox sitcom “Sons of Tucson” (2.0/5, 4.1 million), airing at 9:30 p.m., ticked up slightly from the previous week.

With a rerun-heavy slate of “America’s Funniest Home Videos” (1.8/6, 7.1 million), “Extreme Makeover: Home Edition” (1.9/5, 6.8 million), “Desperate Housewives” (1.3/3, 5.0 million) and “Castle” (1.1/3, 4.4 million), ABC finished fourth on the night in the demo.

Preliminary 18-49 averages for the night: CBS 4.0/11, Fox 2.2/6, NBC 2.1/6, ABC 1.5/4, Univision 0.8/2.

In total viewers: CBS 14.5 million, NBC 6.2 million, ABC 5.8 million, Fox 4.6 million, Univision 2.2 million.