A third season for "Marvel's Agents of S.H.I.E.L.D." is already official, but the show's two-hour second season finale hit a new low rating Tuesday night on ABC.

As reported by various sources including TV By the Numbers, "Agents of S.H.I.E.L.D." drew a series low overnight rating, with a 1.3 among adults 18-49, down from last week's 1.5.

Though the shows don't air head-to-head, The CW's similarly comic book-based "The Flash" (the penultimate episode of that series' first season) attracted a slightly larger audience, 1.4 in adults 18-49. "iZombie," also on The CW and also renewed for next season, saw a 0.7 rating, up from last week's 0.6.

It must be noted that "Agents of S.H.I.E.L.D." has seen significant bumps in the past when Live + 3 and Live + 7 numbers, factoring in DVR viewers, are considered.