MTV’s “Jersey Shore” wrapped its record-breaking third season with impressive numbers Thursday, and stands as TV’s No. 1 series among young viewers for the year.

According to Nielsen, Snooki, “The Situation” and the gang averaged a 4.1 rating/11 share in adults 18-49 and 7.61 million viewers overall to rule the evening’s 10 o’clock hour among young adults over firstrun competition that included NCAA basketball on CBS (3.0 in 18-49), “Private Practice” on ABC (2.6) and comedies on NBC (1.7 average for the combo of “30 Rock” and “Outsourced”).

The finale drew 25% more viewers than the season-two conclusion last October (6.1 million) and 58% more than the show’s rookie-season finale in January 2010 (4.8 million).

Despite the strong numbers Thursday, it didn’t represent a series high for the show, which peaked on Feb. 3 with a 4.5 rating in adults 18-49 and 8.3 million viewers overall.

MTV says that “Jersey” is the No. 1 television series of 2011 among persons 12-34. On Thursday, its 6.2 national rating in the demo topped Fox’s “American Idol” (4.2) by 48%.

A reunion special is on tap for this Thursday, and “Jersey Shore” will return to MTV for a fourth go-round later this year with a season shot in Italy.

In other ratings news, coverage of the NCAA men’s basketball tournament on CBS and Turner Sports was averaging 9.1 million viewers through Saturday, up 11% from last year (8.2 million) and making it the most-watched tourney in six years.

Saturday’s regional semifinals on CBS averaged 9.9 million viewers, also the best since 2005 (when both games on the day went into overtime.)