NBC’s “The Voice” is picking up steam in its second week, dominating its hour on Tuesday and showing week-to-week gains. That helped lead-out comedy “Go On” hold nearly all of its premiere audience, while “The New Normal” dropped off a bit more.

According to preliminary national estimates from Nielsen, “The Voice” averaged a 4.5 rating/14 share in adults 18-49 and 13.3 million viewers overall in the 8 o’clock hour — a healthy 15% jump over its week-ago prelim score (3.9) and 13% higher than its final number (4.0) and the net’s best series result in the hour since December 2009.

That means both of its regular nights showed gains over last week, perhaps due to an early start to the season that may have caught some viewers off guard. Of course, it still continues to track well below last winter’s hot opening-weeks average following the net’s telecast of the Super Bowl.

The music contest was followed by the second-week Tuesday showings of “Go On” (3.3/9 in 18-49, 9.3 million viewers overall) and “The New Normal” (2.2/6 in 18-49, 6.2 million viewers overall), both of which also won their timeslots opposite soft competition.

In a vacuum, the numbers are solid as the former dropped just 3% from its week-earlier slot premiere and the latter eased 12%. But given that “The Voice” was so much healthier this week, “Go On” saw its retention of the 8:30 p.m. half-hour of the reality show dip from 81% a week ago to 67% this week (3.3 vs. 5.0); and “Normal,” which also retained 67% of its lead-in (2.2 vs. 3.3), was down from last week’s 74% hold.

Any way you slice it, though, both will face tougher competition in the coming weeks with comedies on Fox and ABC both joining the 9 o’clock hour, which also houses hit drama “NCIS: Los Angeles” on CBS.

Closing out the night for NBC on Tuesday was drama “Parenthood” (1.8/5 in 18-49, 5.0 million viewers overall), which was down a tick from its week-earlier premiere but still prevailed among the broadcast networks .

Elsewhere, there wasn’t much else happening, with Fox original “So You Think You Can Dance” (1.6/5 in 18-49, 4.6 million viewers overall) tying with ABC’s special “20/20: Best in TV with Barbara Walters” (1.6/4 in 18-49, 7.4 million viewers overall) and CBS’ repeat “NCIS” (1.6/5 in 18-49, 10.2 million viewers overall) as the night’s top non-NBC performers among young adults.

This was the season finale for Fox’s “Dance,” which was up slightly week to week for its best 18-49 score in a month.

Next Tuesday will see the series premieres of CBS drama “Vegas” and Fox comedies “Ben and Kate” and “The Mindy Project.”

Preliminary 18-49 averages for the night: NBC, 3.1/9; Fox, 1.6/5; CBS and Univision, 1.5/4; ABC, 1.4/4; CW, 0.3/1.

In total viewers: CBS, 8.8 million; NBC, 8.7 million; ABC, 6.3 million; Fox, 4.6 million; Univision, 3.6 million; CW, 0.6 million.