The Voice isn't going to be a one-hit ratings wonder for NBC, apparently.

Monday night's regular time-period premiere of The Voice's second season dominated the television ratings, averaging 17.8 million viewers and a 6.7/17 rating/share in the Adults 18-49 demographic during its 8-10PM ET broadcast period, according to "live plus same day" figures from Nielsen Media Research.

The Voice also finished first among the Adults 18-49, Adults 18-34, Adults 25-54, and total viewers ratings categories in every half-hour period during its two-hour broadcast despite airing against first-run broadcast network competition (including The Bachelor) from all four of ABC, CBS, Fox, and The CW.

The ratings performance ranks as NBC's highest Adults 18-49 rating for a regular-season entertainment broadcast on any night since Heroes in September 2007.  In addition, it also represents NBC's highest non-Olympics viewership in the Monday time period in five years and biggest non-Olympics Adults 18-49 rating in the time period in nearly eight years.

Monday night's The Voice episode followed Sunday night's special post-Super Bowl broadcast of the singing competition's second-season premiere, which averaged a 16.3 rating among Adults 18-49 and 37.6 million viewers during its 10:19-11:21PM ET time period.

The post-Super Bowl episode's ratings ranked as the highest Adults 18-49 rating for any television entertainment program since ABC's post-Super Bowl telecast of Grey's Anatomy in February 2006. 

In addition, The Voice's post-Super Bowl episode also ranked as NBC's highest-rated entertainment telecast among both Adults 18-49 and total viewers since the network aired the series finale of Friends in May 2004.

Both second-season broadcasts significantly exceeded the ratings of any episode of The Voice's first season, which premiered last April and concluded in June.

The Voice's first-season delivered a high of 14.4 million viewers for its May 31 first-season broadcast which aired following the season premiere of America's Got Talent and a Adults 18-49 rating high of 5.7 for its May 3 broadcast.

Overall, The Voice's first season averaged 13.7 million viewers and a 5.5/15 rating/share among Adults 18-49 -- which had left it as the surprise #1 new series of the 2010-2011 season among Adults 18-49 and behind only American Idol among all entertainment series on ABC, CBS, NBC, Fox and CW last season.