"Chuck" might not be a flash in the pan after all.

The return of the cult favorite NBC series earned a 4.3 rating/7 share in Fast National ratings from The Nielsen Co., topping its Sunday performance, and posting the best Monday scripted ratings on NBC since "Trauma" premiered Sept. 28.

The success didn't follow through to other shows, however, as "Heroes" matched a series low from the previous week in its new 9 p.m. timeslot, and the added publicity for Jay Leno didn't do much to boost the Monday ratings of his show.

"Heroes" earned a 2.9/4, according to Zap2it, losing nearly 33 percent of its lead-in audience from "Chuck." In fact, "Heroes" was NBC's lowest-rated show of the night as "Jay Leno" built on its lead-in by nearly 7 percent to finish with a 3.1/5.

"Heroes" is now nearly 26 percent off its already low-rated season premiere, and almost 15 percent off its season average. The low matches what it did in the second hour of its previous week after posting a 3.4/5 in the timeslot now occupied by "Chuck."

If NBC didn't have much of a case to think about pulling "Heroes" from the air, back-to-back outings featuring a sub-3.0 household rating might be the final nail.

"Chuck," however, seems to be the mild success NBC has been looking for. After finishing Sunday with a 4.1/7 average, "Chuck" built on its audience rather than see a traditional slip after the premiere to show it may have the staying power needed to anchor Monday nights. This particular outing was nearly 8 percent better than its season average last year.

Averaging a 4.2/7 over its first three episodes, "Chuck" is doing nearly 11 percent better than it did the first three episodes of last season. It's the best start for "Chuck" since the 2007-08 season when it averaged a 5.2/8 over its first three episodes ever. Right now, "Chuck" is just 19 percent off that original pace.

"Fringe" showed it might possibly be on the wrong night. It earned a season high-matching 4.7/7 as a lead-out from "House," topping its season average so far by 24 percent. It also was 24 percent better than its most recent episode aired on a Thursday, a 3.8/6 on Dec. 10.

"Fringe," however, still lost nearly 36 percent of its lead-in show, and was still 25 percent off its first season average.

Fast Nationals usually provide a snapshot of what Americans are watching by pulling numbers from the top urban markets that includes both live viewing and same-day timeshifted viewing. A rating point generally represents more than 1.1 million households while the share indicates the percentage of televisions turned on that was tuned to the specific program. These numbers typically shift when final ratings are issued.