Juventus coach Massimiliano Allegri insisted the Serie A title race is far from over after a sensational first-half strike from Colombian Juan Cuadrado sent the Turin giants six points clear of Napoli on Sunday.
Roma, currently third at seven points behind, can move back up to second place with a win over Fiorentina in their delayed game on Tuesday.
But the capital club, still reeling from a 3-2 defeat to Sampdoria last week, are now under huge pressure not to drop further points following another defiant display from the 32-time champions in Turin.
Inter travelled west hoping to build on a superb spell of form that has seen Stefano Pioli's men claim 25 points from their last 10 games.
But poor finishing and dogged Juve defending kept Inter at bay in a promising first half before Cuadrado put a smile on Allegri's face with a slightly-deflected shot that beat Samir Handanovic at his top corner on 45 minutes.
Juve held on amid an at times bad-tempered second half, Ivan Perisic seeing red in the final minute, to secure an 18th win that kept them on course for a record-setting sixth consecutive title.
But Allegri, who admitted to now being happy Inter's "slow start" to the campaign, said the title race is far from over.
"We're not going to say we have one hand on the scudetto, but this is a very important step," Allegri told the Domenica Sportivo programme post-match.
"I'm sure that Napoli and Roma have yet to collect a lot of points, but in the meantime we've kept a rival like Inter at bay."
Inter, chasing a coveted Champions League place, remain fifth at 12 points adrift and five points behind Roma in the third and last Champions League spot.
The gap on Roma will grow to eight points if Luciano Spalletti's men turn around a recent spell of mediocre form to beat La Viola on Tuesday.
It left Inter coach Stefano Pioli even more annoyed after claiming his side were denied two clear penalties in the opening half following alleged fouls on Mauro Icardi by Mario Mandzukic and Giorgio Chiellini.
As Juve, Napoli and Roma look to tighten their grip on the Champions League place, Inter are staring at fighting for a place in next season's Europa League.
If there is any consolation, it was in seeing city rivals AC Milan slip to a third consecutive defeat after Luis Muriel hit a second-half penalty to earn a 1-0 San Siro win for Sampdoria.
AC Milan coach Vincenzo Montella had raised hopes this season that the seven-time European champions could battle for a Champions League spot for the first time since 2014.
But injuries to midfielder Giacomo Bonaventura, who is out for the season, and defenders Mattia Di Sciglio and Luca Antonelli forced Montella into deploying a largely makeshift back four.
Alessio Romagnoli and Juraj Kucka were hauled back into defence from midfield and the enforced changes exacted a toll.
When Gabriel Paletta hauled down Fabio Quagliarella on the counter, the referee pointed immediately to the spot. Muriel sent goalkeeper Gianluigi Donnarumma the wrong way in the 70th minute.
Milan remain in eighth place but are now 17 points behind leaders Juventus.
"The Europa League is our primary objective," admitted Montella.
Elsewhere Sunday Marco Parolo scored four times, three with his head, as Lazio hammered bottom side Pescara 6-2 to maintain their Champions League challenge to remain fourth, at four points behind Roma.
Palermo gave their relegation dogfight a shot in the arm with a 1-0 win over 10-man Crotone that kept the Sicilians third from bottom but now eight points from the safety zone.