After back-to-back draws to start their campaign, Portugal have now recorded much-needed wins over Serbia and Lithuania this week.
And Ronaldo feels Portugal – in second spot and holding a game in hand – are now closing in on a place at next year’s showpiece tournament.
“The hardest thing was winning in Serbia, and it was important to continue with a triumph here,” added the forward.
“We are closer, we have two games – one at home and one away – and I think if we win one of those matches it’s enough.”
Next up for Fernando Santos’ side is a home clash with Luxembourg in Lisbon on October 11 before a trip to Kiev to take on group leaders Ukraine three days later.