Title challengers Inter are capable of keeping pace with Juventus throughout the entire Serie A season, according to Marcello Lippi.
Antonio Conte's men notched up a fourth successive league win with a routine 3-0 triumph at Torino on Saturday.
Goals from Lautaro Martinez, Stefan de Vrij and Romelu Lukaku kept the pressure on champions Juve, who remain a point ahead after a 3-1 win over Atalanta.
Some have suggested strength in depth will enable the leaders to pull clear as the season progresses, but Lippi expects the title race to go down to the wire.
"It is very beautiful and it certainly made the start of the season very interesting," the ex-Italy head coach told Corriere dello Sport.
"I really think it can last until the end. In August I thought that it would be a three-way fight for the title, but Napoli will struggle to get back into the race.
"[Carlo] Ancelotti is a very good coach and I am convinced that he will improve the team. However, even if he drives them out of the difficult moment he is going through, he has accumulated too much distance to the top.
"The championship will be more uncertain than in recent years and this is good for our football."
Inter's only domestic defeat this term came at the hands of Juve in October.
Lippi praised Bianconeri boss Maurizio Sarri for adapting well to the job he inherited from Massimiliano Allegri.
He said: "The change of coach could have negatively affected and created difficulties if Sarri had not been intelligent, but Maurizio is intelligent.
"He has already managed to implement some of his ideas without lowering the performance that Juve had with Conte first and then with Allegri."