HOLLYWOOD — Ever since “The Fresh Prince” bailed on Bel-Air about five years ago, Monday night at 8 has been one of the weakest links of an otherwise strong NBC schedule.

Not anymore.

Thanks in part to the tart-tongued antics of host Anne Robinson, gameshow “The Weakest Link” has attracted a substantial following in its first two Monday broadcasts, easily winning its hour both weeks. According to Nielsen, “Link’s” initial airings have boosted the NBC time period by 90% in the key demo of adults 18-49.

“Link’s” success means NBC has joined both Fox and CBS this season in effectively using nonscripted series to fill vexing time periods. ABC was actually the first net to do this — last season — when it added quizzer “Who Wants to Be a Millionaire” to its Thursday and Sunday lineups.

In the case of NBC, while “Weakest Link” is off to a solid start, it would almost certainly perform even better as a weekly series in a stronger, higher-profile slot. Indeed, a three-night rollout of the quizzer in mid-April produced better ratings on both Tuesday and Wednesday, but NBC doesn’t need the help there.

The Peacock has lagged well behind its rivals Mondays this season, but in the first two weeks with “Link” in the leadoff hour, it has moved up to a strong second. “Link” itself helped NBC win the 8 p.m. hour in key demos for two consecutive weeks for the first time in nearly four years.

NBC now knows that, unless “Link” completely fizzles over the summer, it has a solid (and relatively cheap) utility player to fill a hole next season — likely on either Sunday or Monday.

“Temptation Island” and, to a lesser extent “Boot Camp,” have been even more of a boon for Fox, invigorating a Wednesday 9 p.m. hour that had been dragging the net down for the first three months of the season. And the big scores pump up Fox’s averages even more than the other nets’ “game-changers” since Fox programs only 15 hours vs. 22 for ABC, CBS and NBC.

Since the beginning of January (when “Temptation” premiered), Fox has won all but two weeks in its target adults 18-34 demo to take control of that category for the season. It’s also closed the gap significantly with leader NBC in 18-49.

Even the current-running “Boot Camp,” while posting numbers considerably lower than what “Temptation Island” netted a few months earlier, is improving the time period vs. a year ago for Fox by more than 50% in young-adult demos.

And then there’s “Survivor: The Australian Outback,” which inherited a CBS Thursday slot occupied a year ago by the geezer show of primetime, “Diagnosis Murder.” Compared with the creaky drama’s averages of last season, “Survivor” is delivering demos three, four and in some instances seven times greater than the Eye saw a year ago.

This, combined with boffo scores for the show airing behind “Survivor” — “CSI: Crime Scene Investigation” — has helped make CBS a legitimate demo player for the first time in nearly a decade.

The Eye web has won six weeks in adults 18-49 this season after failing to notch a single victory a year ago; it also is poised for a solid second-place finish in its target 25-54 demo.

The “Survivor” franchise is so hot that the Thursday timeslot made a lot of sense for Eye programmers: Viewers were going to tune in wherever it aired, so why not let it turn on some lights on Thursday?

A stronger CBS on Thursday, Fox on Wednesday and NBC on Monday can also only help make the broadcast nets stronger as a whole.

This season, the Big Four webs will finish down about 1% in total viewers and key demos vs. a year ago — and this is considered a victory at a time when the 100-channel cable universal continues to chip away at the broadcast nets’ share of the viewing pie.