The episode gave Supergirl its best rating since early February with 7.24 million viewers tuning in, which is up from the previous episode of 6 million.
The 7 million viewers is also almost more than two times what The Flash on the CW normal sees (around 4 million).
Supergirl also beat Fox's Gotham, as the two air at the same time, with Gotham netting 4.78 million.
The episode was a bit corny for my taste (poor choice in villains, and I could do without the Kara and Jimmy Olsen romance), but seeing Supergirl and The Flash on screen together was pretty cool. Grant Gustin and Melissa Benoist have some good on screen chemistry.
More than likely with the ratings success, this will mean further crossovers down the line with Supergirl, Flash, Arrow and DC's Legends Of Tomorrow, which Gustin said was the plan.
Update: CBS released the following official announcement:
“SUPERGIRL” SOARS WITH “THE FLASH” CROSSOVER
“Supergirl” Leaps +31% in Adults 18-49 to a Seven-Week High and Increases +21% in Viewers
Tops All Monday Scripted Programs in Adults 18-49
SUPERGIRL delivered its biggest adults 18-49 rating in seven weeks and its largest audience in five weeks with last night’s “The Flash” crossover episode, according to Nielsen preliminary live plus same day ratings for Monday, March 28.
In adults 18-49, SUPERGIRL averaged a seven-week high of 1.7, a +31% jump from a week ago. In viewers, the crossover episode averaged 7.24 million viewers, up +21% from last week and delivering its largest audience in five weeks.
SUPERGIRL was Monday’s highest-rated scripted series in adults 18-49.