Leicester City are seven points clear at the top of the Premier League table, but manager Claudio Ranieri is still wary of his side's five "terrible" tests to come.
Leicester face a tough run in, with matches against West Ham, Swansea City, Manchester United, Everton and Chelsea still to play.
Three wins from their last five games would be enough to secure the title, regardless of what Tottenham - who sit in second - do with their five remaining fixtures.
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 emotion 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."