This is totally off-topic for this site but I really had to take not of this really interesting question that I saw asked on Quora:

This is something which has happened so many times with me now. Have you had similar incidence? What was your reply when your boss asked that question? Or what would you reply if in future you face such a question?

The following answer provided could not be more eloquent:

Take advantage of the opportunity to get valuable face time with your boss. I'd recommend something like:

"I was under a lot of pressure, but things seem to be flowing well now. I've got a firm grip on the situation and am seeing some good output. It may take awhile before I achieve completion, but it's important to take one's time in order to stay on target. I expect to wash my hands of the whole thing in the next several minutes."