Despite sitting top of the table and seven points clear, Ranieri is wary of five tough matches still to come for Leicester.
West Ham, Swansea City, Manchester United, Everton and Chelsea are the teams left for Leicester to play.
Three wins from five matches will hand them the EPL, no matter what Tottenham do.
But Ranieri says there is still work to do.
“It’s not done yet,” he said. “We are in the Champions League – at least, in the preliminary round of the Champions League.
“But the last five tests will be terrible. Tottenham didn’t give up and we have to stay focused.”
Ranieri was visibly emotional after Leicester’s 2-0 win over Sunderland, appearing to shed a tear or two, but the Italian said he would try to contain his emotions for the rest of the title run-in.
“They were not real tears. They were unshed tears. It was a moment of emotion,” he said.
“To see all those people around us, entire families on the buses with the Leicester shirts, who have followed us up to Sunderland, it struck me deeply.
“You realise, in these cases, the extraordinary power of football. When our sport manages to pull off this positivity, you cannot remain indifferent.”