CBS took the overall ratings crown on Thursday night on the strength of "Big Brother," while ABC's recently launched reality series "Expedition Impossible" felt a considerable slide, according to preliminary numbers.

"Big Brother," on CBS at 9 p.m., grew 4 percent from last Thursday, easily taking the top-rated slot with a 2.7 rating/8 share in the adults 18-49 demographic and 7.2 million total viewers. With the network running repeats throughout the rest of its primetime roster, that was enough to give CBS the top overall numbers for the night with a 1.8/6 in the demographic.

ABC received lukewarm to grim news in last night's numbers; "Wipeout" launched the evening at 8, performing flat with last week's airing with a 1.9/7 in the demographic and 6.5 million total viewers.

"Expedition Impossible" aired the following hour, dropping 13 percent compared to last week with a 1.4/4 and 4.7 million total viewers. "Rookie Blue" finished out the night, tying with last week's summer low with a 1.3/4 and 5 million total viewers.

Fox launched its night with "So You Think You Can Dance," which slipped 6 percent for a 1.6/6 in the demographic and 5.1 million total viewers. A "Glee" repeat finished out the evening at 9.

NBC ran repeats throughout the evening.