While Supergirl and The Flash both do fairly well in the ratings on their own, a team-up between the two is superheroic.
The crossover episode, bringing The Flash from The CW to CBS's Supergirl, gave a huge boost to the ratings of the latter show, with a 31% increase in demographic rating up to 1.7, and a 21% increase in total viewers - 7.24 million people tuned in live to see the event.
Surprisingly, that's not Supergirl's top episode ever, but it is its highest in almost two months.
Gotham posted solid numbers with a 3.8 million total viewer and 1.3 demo rating, and Lucifer held strong, keeping all the total viewers and a 1.2 rating. Of the three Monday night DC Comics shows, only Gotham has been officially renewed, though Supergirl's renewal is just a matter of time at this point.