Lewington said: "If they play like that they will be relegated, but I hope they won't. Everything that could go wrong went wrong today.
"But we are realistic enough to know that the performance was not good either and we have got to put that right.
"In the first half we changed the shape, with the record we have away from home. We went into a 4-3-3 system and it made us a little bit more solid in the middle and gave us pace on the flanks.
"But we didn't do the basics. Stopping them play. You can't do that against a side of Spurs' talent. That is always a risky thing. I'm looking back and thinking whether I should have changed the shape. Perhaps I could have stayed 4-4-2."
John Collins remains the favourite for the job after quitting Hibs last week, and Martin Jol is also in the frame for a return to management.
Lewington added: "I don't know whether I am in charge this weekend.
When I was told to take over last week it was a case of getting on with it until being told someone else is coming in. If they make a change before then, fine."