Part 1 of the NBC’s America’s Got Talent season finale last night averaged 13.7 million viewers and a 2.7 among adults 18-49 in the fast nationals.  Those numbers, which sometimes are adjusted up in the finals, are up from last Tuesday (2.5, 12 million) as well as up from the same night last year by +13% in the demo and by +20% in total viewers.

The performance finale of the first AGT cycle with co-creator Simon Cowell as a judge also matches its season high in 18-49 and hit a five-year high in total viewers (best since Sept. 14, 2011, 14.4 million). The summer staple already has been renewed for next year with all four judges set to return.

AGT also lifted the finale of NBC’s new unscripted show, Better Late Than Never (1.7, 7.8 million viewers), which inched up to series highs in 18-49 and total viewers.

NBC dominated the night with a 2.4 in 18-49 and 11.7 million viewers. CBS was second, paced by the only other original offering on the Big 4 a night, a special Tuesday Big Brother (1.8 in 18-49, 6.4 million), which was about average. At the CW, MadTV (0.2) was flat.