Antonio Conte's side are ahead of second-placed AC Milan, who beat Hellas Verona 2-0 on Sunday, with champions Juventus 10 points off top spot, with a game in hand, after a 3-1 win over Lazio
Milan Skriniar scored the only goal as Inter Milan moved back six points clear in Serie A with a 1-0 win over Atalanta on Monday.
Inter extended their winning streak to seven league games as they push for a first title since 2010.
Antonio Conte's side are ahead of second-placed AC Milan, who beat Hellas Verona 2-0 on Sunday, with champions Juventus 10 points off top spot, with a game in hand, after a 3-1 win over Lazio.
Skriniar found a way through after 54 minutes sending in off fellow defender Alessandro Bastoni after a corner resulted in a scramble on front of goal in the San Siro.
"Knowing that the closest direct pursuers had won it's inevitable that there was pressure, these are three important points," said Conte.
Seven straight league wins and six points clear at the top of Serie A.— B/R Football (@brfootball) March 8, 2021
Inter are loving life right now 😘 pic.twitter.com/sIl71A41LT
Atalanta are fifth, outside the Champions League berths, and 13 points off top spot with 12 games left to play this season.
"We put in a great performance and lost on a corner," lamented coach Gian Piero Gasperini whose side are one point off fourth-placed Roma.
"Against Inter and Juventus we always lack that little detail we don't yet have, but we are close."
In a clash between the two biggest scoring teams in Serie A the defenders decided the tie with Atalanta's Berat Djimsiti giving little space to the Inter attackers.
Romelu Lukaku and Lautaro Martinez lead the Inter attack, the best in the Italian top-flight with 63 goals.
Atalanta are second best with 60, with forward Duvan Zapata starting up front, being replaced by fellow Colombian Luis Muriel for the final 20 minutes.
Chances were few in the first half.
Atalanta goalkeeper Marco Sportiello used his head to clear for a corner off a Cristian Romero cross after quarter of an hour.
- Six points clear of Milan— ESPN FC (@ESPNFC) March 8, 2021
- Ten points clear of Juventus
Scudetto loading for Inter?! 🏆 pic.twitter.com/1mTn5AWAJ5
Inter goalkeeper Samir Handanovic denied a Zapata header six minutes before the break and Marcelo Brozovic was cleared off the line just after.
Josip Ilicic replaced Ruslan Malinovskyi after the break for Atalanta with Conte sending on Christian Eriksen in place of Arturo Vidal.
And the Dane's corner which resulted in the goal, Skriniar's third in the league this season.
Inter threated a second just after but Romero slid in to deny a Lukaku finish just before the hour.
"One goal but we missed sensational opportunities," said Conte.
"It was a very tactical match."
Atalanta broke their four-match winning run in Serie A as they remain in the running in the Champions League and the Italian Cup final.
Inter are without European commitments with nothing left to target but the league and are next at relegation-threatened Torino.
Atalanta play at home against promoted Spezia before their Champions League last 16, second leg visit to Real Madrid.