Dont know what was going on

I left my headlights on by accident over night and it killed my battery however the nxt morning when i tryed to start my car is when i noticed it was dead so my friend and i hooked up booster cables but i didnt have the key in the ignition yet but my car started right after the boosters were connected. Is it possible that the ignition could have had a delay due to there not being enough power to the car?