The two-hour season finale of “Grey’s Anatomy” managed to rank ABC to No. 1 in the ratings on Thursday, attracting 17.8 million viewers from 9 to 11 p.m., according to Nielsen’s estimates.

Even though the number of viewers for the show’s fourth-season declined by nearly 5 million from a year ago, “Anatomy” still led the night by a wide margin over its nearest competitor, NBC’s “Deal or No Deal,” which gathered 10.3 million viewers from 8 to 9:30 p.m.

“Grey’s Anatomy” delivered the highest 18-49 rating for a scripted program in more than three months, since Fox’s “House” on Feb. 5.

NBC aired “Deal or No Deal” (2.5/8 in 18-49, 10.3 million viewers overall) followed by the season premiere of “Last Comic Standing” (2.4/6 in 18-49, 7.2 million viewers overall, Variety reports.

Meanwhile, CBS had a weak night. Following special repeats of comedies “The Big Bang Theory” (1.2/4 in 18-49, 4.3 million viewers overall) and “How I Met Your Mother" (1.5/5 in 18-49, 4.5 million viewers overall), repeats of “CSI” (1.6/4 in 18-49, 6.5 million viewers overall) and "Without a Trace" (1.7/4 in 18-49, 7.7 million viewers overall) both did little business.

Preliminary 18-49 averages for the night: ABC, 5.5/16; Fox, 3.4/10; NBC, 2.4/7; Univision, 1.6/5; CBS, 1.5/4; CW, 0.7/2.

In total viewers: ABC, 14.8 million; Fox, 8.6 million; NBC, 8.1 million; CBS, 6.2 million; Univision, 3.7 million; CW, 2.0 million.