CBS is on track to win last week in total viewers and adults 18-49 despite a big primetime football game on Fox on Saturday. CBS too got some help from football, with an NFL overrun on Sunday, but its big MVPs of the week were The Big Bang Theory and NCIS, both of which crossed the 20 million total viewer mark in Live+Same Day. For Big Bang, the 20.0 million was a new total-viewer high (the comedy also hit an all-time high in 18-49, 6.7/19), while for veteran NCIS, the 21.1 million was a season high (NCIS‘ 18-49 average was a 3.5/10).

How big was Big Bang and NCIS‘ feat? The last time any network had two scripted series draw more than 20 million viewers in Live+SD during the same week was more than five years ago, the week of November 5, 2007, when CBS’ CSI delivered 21.9 million and Without A Trace followed with 21.6 million.

Both NCIS and Big Bang are hitting the high marks well into their runs — NCIS is in its 10th season, Big Bang in its sixth. Both series have seen ratings pick up after they launched in off-network syndication, particularly NCIS‘ run on USA Network and Big Bang‘s on TBS. (NCIS‘ current series high in total viewers, 22.9 million, was posted after the drama started airing repeats on USA — during the series’ eighth season). Both shows have been very successful on cable, with Big Bang continuing to sizzle on TBS where it launched in fall 2011. CBS’ entertainment president Nina Tassler recently crediting Big Bang‘s extra exposure for its recent surge as the comedy has hit a string of series highs this season, including in each of its two most recent airings. “The success it’s having in syndication cycles back and gives us, I think, that bump on broadcast,” she said at TCA last week. “It’s also a great show. I think that they’ve really evolved it.” Indeed, the larger cast of the show has jelled, and the comedy has delivered some instant classic episodes this season, like the one where Sheldon takes care of flu-stricken Amy or the one where Sheldon deals with HR sexual harassment complaints.

The burst in popularity for Big Bang does coincide with the show’s previous seasons becoming widely available, not only in syndication but also online. Series producer Warner Bros TV is well known for being very protective, not allowing online streaming of any of its comedies or procedural dramas until they launch in syndication. Big Bang is now finally available on, immediately spiking to No. with more than 1.2 million streams season to date. It also started airing repeats on Monday in CBS’ traditional comedy block following the cancellation of Partners, which may have helped bring additional viewers to Thursday. Another potential factor for Big Bang‘s recent surge — its two most recent episodes, both of which posted series highs, were the first this season to air without NFL competition on cable that draws a similar young, male-skewing audience.