Just a few seasons ago, the 10 p.m. timeslot was being written off as a dead zone, as viewers turned to their DVRs to catch up on programming during the hour.

Now it’s the savior of the fall season: The only three breakout shows in an otherwise lackluster slate all air in the late hour: NBC’s “Blindspot,” CBS’ “Limitless” and ABC’s “Quantico,” with each show improving the time period for its respective network.

Otherwise, it’s been a challenging rollout to say the least. Viewers aren’t sticking with new comedies earlier in the evening, and no new series has rated nearly as high as last fall’s top launches (“How to Get Away With Murder,” “Gotham” and “Black-ish”).

NBC is the network off to the best start overall, riding a balance of successful new and returning shows (plus “Sunday Night Football”) to rule the 18-49 demo.

“Blindspot” is the highest-rated among them, owing in part to its strong “The Voice” lead-in, but it has also been a monster gainer in delayed viewing. Its audience composition is reminiscent of “The Blacklist,” which opened in the same Monday timeslot in 2013. NBC rewarded the show with a full-season pickup after strong ratings for its third episode.

As an action show with a younger lead, “Limitless,” based on the Bradley Cooper film, may be a CBS template for attracting younger viewers. It’s building on its “NCIS: New Orleans” lead-in by 30% in men 18-34, but its stiffest challenge comes starting this week with the timeslot return of NBC’s tough “Chicago Fire.”

“Quantico” has impressed on Sunday, building sharply on its lead-in from another new show, “Blood & Oil,” and becoming the only scripted rookie to grow its “live plus-3” audience in week two. It’s also garnered the most critical support among new fall dramas, according to review aggregator Rotten Tomatoes.

These three shows give the networks some stronger assets in the final hour of primetime, which is typically a busy one for DVR playback. A 10 p.m. hit can certainly help the networks in late-night, with Jimmy Kimmel, for example, scoring his best numbers on Thursdays after the network’s hit Shonda Rhimes dramas.

On the comedy front, viewers don’t seem too excited about the new shows, though ABC, the hottest network in the genre, is doing OK. It got a sizable, nostalgic crowd to sample “The Muppets,” but the show faded some over the next two weeks, and its “Dr. Ken” opened OK on low-expectation Friday and had a pretty good week-two hold.

Fox started from scratch on Tuesday, but “Grandfathered,” “The Grinder” and “Scream Queens” have fallen after OK starts and the network is deep in fourth place on the night. The Rob Lowe-fronted “Grinder” was the fall’s best-reviewed comedy, according to Rotten Tomatoes.

CBS, seeking its first single-camera comedy hit, is faring modestly with “Life in Pieces.” It has decent numbers because it airs behind “The Big Bang Theory,” but it’s now fumbling away about half of the veteran’s young-adult audience.

The nets still have a couple of comedies to roll out in the coming weeks — NBC’s “Truth Be Told” and CBS’ “Angel From Hell” — but neither appears to be a sitcom savior.