Save The Day Meaning

(idiomatic) To rescue a person or situation from imminent danger or major failure.

Example: 1881, Horatio Alger, From Canal Boy to President or The Boyhood and Manhood of James A. Garfield, ch. 25
  [H]e acted as chief of staff to General Rosecranz, aiding his superior officer at a most critical point in the battle by advice which had an important influence in saving the day.
1912, Arthur B. Reeve, The Poisoned Pen, ch. 6:
  "It's Paddy," cried Craig. "If he can bring them all out safely without the loss of a life he'll save the day yet."
1991 June 24, John Skow et al., "Life In The Age Of Lyme," Time:
  An effective vaccine would save the day and last year researchers at Yale were reporting some progress.
2008 May 28, Eugene Robinson, "The ravages of the Clinton campaign," San Francisco Chronicle:
  Maybe a strapping woodsman will come along and save the day.