CBS reality veteran “Big Brother,” which has gotten off to a sluggish ratings start this time around, showed its first spark of this summer Sunday by dominating its time period on what was a lackluster night overall for the Big Four.

“Big Brother” had traditionally started after the Fourth of July but began in late June this year, which may have caught some fans off guard. But on Sunday it grew about 10% from last week, averaging a 2.1/6 in 18-49 and 6.2 million viewers overall in the 8 o’clock hour. It was Sunday’s No. 1 broadcast in adults 18-49 (2.1/6) and adults 25-54 (2.5/7) while finishing second in total viewers to lead-in “60 Minutes” (1.0/3 in 18-49, 7.6 million viewers overall).

Following “Big Brother,” CBS rebroadcast the second episode of new Monday drama “Under the Dome” (0.9/2 in 18-49, 4.1 million viewers overall), giving it more exposure prior to its third episode tonight. And at 10, the Eye aired a repeat of “The Mentalist” (0.7/2 in 18-49, 3.8 million viewers overall).

SEE ALSO: CBS’ ‘Big Brother’ Back on Familiar Schedule Turf

Fox tied CBS in adults 18-49, led by its 8 to 10 p.m. block of animated repeats: “The Simpsons” (1.4/5 in 18-49, 3.1 million viewers overall), “Bob’s Burgers” (1.3/4 in 18-49, 2.7 million viewers overall), “Family Guy” (1.7/5 in 18-49, 3.5 million viewers overall) and “American Dad” (1.5/4 in 18-49, 3.0 million viewers overall). From 9 to 10 p.m., “Guy” and “Dad” led among the broadcasters in 18-49.

ABC wasn’t much of a factor on the night despite airing original hours “Celebrity Wife Swap” (0.9/3 in 18-49, 2.9 million viewers overall) and “Whodunnit?” (1.0/3 in 18-49, 3.0 million viewers overall) from 8 to 10. “Wife Swap” was down slightly, while “Whodunnit?” was steady.

ABC bookended the night with repeats of “America’s Funniest Home Videos” (0.9/3 in 18-49, 4.5 million viewers overall) and “Castle” (0.6/2 in 18-49, 3.0 million viewers overall).

NBC went with a two-hour “America’s Got Talent” encore (1.0/3 in 18-49, 4.1 million viewers overall), followed by a repeat “Law & Order: SVU” (0.8/2 in 18-49, 3.6 million viewers overall) and an original episode of struggling new drama “Crossing Lines” (0.6/2 in 18-49, 2.8 million viewers overall).

Preliminary 18-49 averages for the night: CBS and Fox, 1.2/4; Univision, 1.1/3; ABC and NBC, 0.9/3.

In total viewers: CBS, 5.4 million; NBC, 3.7 million; ABC, 3.3 million; Fox, 2.7 million; Univision, 2.4 million; Telemundo, 1.6 million.