Should Roma prevail at Chievo and Inter draw or lose, then the Romans would win the championship for the first time since 2001 as they hold a better head-to-head record.
"I ask our fans and my team-mates not to give up hope," said Totti.
"We head into the final weekend of the campaign and we still have a chance to win the scudetto.
"We will fight until the last second to get a win at Chievo and wait to see what happens at Siena."
Inter coach Jose Mourinho admits his players could be distracted heading into Sunday's game in Tuscany.
"We have 15 days of madness," he said.
"I want my players to be European champions."