“So You Think You Can Dance” helped lift Fox to victory among young adults on Thursday, a night that saw more declines for CBS drama “Swingtown” and a credible premiere for ABC medical series “Hopkins.”

According to preliminary nationals from Nielsen, “So You Think You Can Dance” (3.0 rating/9 share in adults 18-49, 8.6 million viewers overall) was easily the night’s top-rated program, building nicely on its lead-in from “Are You Smarter Than a 5th Grader” (1.8/6 in 18-49, 6.9 million viewers overall), which claimed a share of first place among young adults in Thursday’s opening hour.

ABC did very little from 8 to 10 p.m. with repeats of “Ugly Betty” (0.8/3 in 18-49, 3.5 million viewers overall) and “Grey’s Anatomy” (0.9/3 in 18-49, 3.4 million viewers overall), but came to life at 10 p.m. with the premiere of limited-run medical documentary series “Hopkins” (1.6/5 in 18-49, 5.8 million viewers overall). Latter placed second in demos at 10 o’clock and first in total viewers.

NBC was led by “Last Comic Standing” (2.1/7 in 18-49, 5.3 million viewers overall), which looks to come in slightly above last week’s performance. And at 10, “Fear Itself” (1.5/4 in 18-49, 4.5 million viewers overall) placed third but has held steady over the last few weeks.

Same can’t be said for CBS drama “Swingtown” (1.9/6 in 18-49, 5.7 million viewers overall), which saw its third straight week of declines following its solid June 5 series premiere. It again built slightly on its lead-in from a repeat “CSI” (1.7/5 in 18-49, 7.2 million viewers overall), while the net was competitive in the night’s opening hour with a repeat of “Million Dollar Password” (1.7/6 in 18-49, 6.8 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 2.4/8; NBC, 1.9/6; CBS, 1.7/6; Univision, 1.6/5; ABC, 1.1/4; CW, 0.5/2.

In total viewers: Fox, 7.7 million; CBS, 6.6 million; NBC, 5.0 million; ABC, 4.2 million; Univision, 3.7 million; CW, 1.6 million.