Barca lost for the first time since the opening day of the season on Saturday, a 2-1 defeat at home to bottom club and city rivals Espanyol which cut their lead to seven points.
Real ran riot at the Bernabeu, knocking six past Real Betis for their ninth straight win.
"It's difficult but it's possible," Ramos said in an interview with Monday's Marca newspaper when asked if his side were still in with a chance of a third consecutive title.
"But to do it we'll have to win all our matches and hope that Barcelona slip up."
Real looked to have little chance of depriving Barca of the title just over a week ago when the Catalans were 12 points clear.
But Barca's 2-2 draw at Betis just over a week ago and Saturday's defeat to Espanyol have reignited a title race that looked to be over. Real defender Fabio Cannavaro said their rivals would be starting to feel the heat.
"Sometimes the tension doesn't let you keep a clear head," he told Real's website. "We have to carry on hoping and see what happens."
Barca captain Carles Puyol said he and his teammates had the self-confidence needed to secure the title even though recent results had not gone their way.
"We know what is required and we have to carry on working in the same way," he said on the club's website. "We are still top and we are still in charge of our own destiny."
