Inter moved six points clear at the Serie A summit as a brace from Alexis Sanchez sealed a 2-1 win away at struggling Parma on Friday (AEDT).
Scudetto rivals Milan were held to a 1-1 draw by Udinese on Wednesday and Antonio Conte's side took full advantage of that slip up to move closer to a first league title since the 2009-10 campaign.
Sanchez, who scored in the weekend win over Genoa, set Inter on their way to a sixth consecutive top-flight win with his fourth league goal of the campaign nine minutes into the second half.
The former Manchester United player added another eight minutes later as Inter, who gave the hosts hope of salvaging a draw when Hernani scored 19 minutes from full time, claimed yet another three points to pull away from their neighbours at the top of the table.
Parma carved out the first clear sight of goal in the contest, Samir Handanovic pawing away Jasmin Kurtic's header in the 15th minute.
A sluggish Inter did not have a shot on target until the 33rd minute when Milan Skriniar's effort inside the six-yard box was well kept out by Luigi Sepe.
The Parma goalkeeper then thwarted Romelu Lukaku after he had been played in by Marcelo Brozovic, while the Belgium international also headed wide before the interval.
However, Inter started the second half brightly and went ahead in the 54th minute when Sanchez's strike from eight yards proved too powerful for Sepe, creeping over the line before Riccardo Gagliolo could clear.
The Chile international claimed his second in the 62nd minute, sliding his finish past an exposed Sepe after a barnstorming run from Lukaku created the opportunity for his team-mate.
Hernani set up a tense finale with a controlled volley from 10 yards from Giuseppe Pezzella's cross in the 71st minute, yet Inter held on to take another significant step towards the title.