not a second too soon

At the last possible moment before it is too late; just in the nick of time. The police arrived not a second too soon, and the would-be burglar was apprehended before anything could be stolen. A: "The surgeon has just arrived." B: "And not a second too soon! This patient needs an operation immediately!" I'm finally getting over this flu, and not a second too soon. If I miss another day of work, they'll start docking my pay!