An estimated 18.6 million people in the US tuned in to watch the debut episode of Joey - the spin-off of Friends.
Joey, starring Matt LeBlanc, is set in Los Angeles
Television channel NBC said it was their best-rated comedy premiere in that evening slot in 14 years.
But the figures are lower than any episode of Friends drew in its last season - including the 24.5 million people who watched the series debut.
The first episode of Joey, starring Matt LeBlanc, was aired on Thursday night, after a huge build up.
NBC said that Joey enjoyed the largest audience among the advertiser-friendly 18-to-49-year-old age group of any other entertainment show since May.
The series had been heavily promoted on the channel during the Olympics.
However, Marc Berman, a television analyst for Media Week Online, said: "I can't imagine they're all there [at NBC] jumping for joy.
"Joey should settle in to being a respectable hit, but it won't be a breakout hit," he added.
The spin-off stars Matt LeBlanc's dim-witted character Joey Tribbiani, with Sopranos actress Drea De Matteo as his newly-installed sister Gina.
It follows Joey's life as an aspiring actor as he tries to make it big in Los Angeles.