Torino defender Armando Izzo turned goal scorer as Inter Milan missed the chance to close the gap on second-placed Napoli in Serie A with a 1-0 defeat in Turin while Roma also proved wasteful, blowing a three-goal advantage to draw 3-3 with Atalanta on Sunday.
Izzo headed in the only goal to get Torino back winning after their defeat last weekend to Roma.
Inter are now eight points adrift of Napoli who were held 0-0 by AC Milan at the San Siro on Saturday.
Champions Juventus travel to Lazio later on Sunday looking to extend their lead on top of Serie A to 11 points, as they chase an eighth consecutive Scudetto.
Inter winger Ivan Perisic was dropped amid transfer speculation, with captain Mauro Icardi starting up front alongside Lautaro Martinez.
But Torino piled on the pressure and it paid off early with Izzo meeting a Cristian Ansaldi cross to head in after 35 minutes.
Substitutes Radja Nainggolan and Matteo Politano failed to turn things around in the second half with Politano sent off late for arguing with the referee.
AC Milan are now five points behind Inter with Roma a further point back in fifth. Torino are tenth but just five points off the Champions League places.
Roma could have overtaken AC Milan but Colombian forward Duvan Zapata continued his goal-scoring streak to snatch a point for Atalanta.
Roma had been three goals up following an Edin Dzeko brace, with Stephan El Shaarawy adding a third five minutes prior to the break, before the Romans faded under the driving rain in northern Italy.
"The problem is this isn't the first time it has happened to us," said Roma coach Eusebio Di Francesco.
"What drives me crazy is the lack of consistency from this team, even during the same match.
"It's absurd to see a team with the same players put in such a different performance from one half to the next.
"We were fortunate to get a draw."
Dzeko broke through after just three minutes for his first goal in Serie A since October, adding a second half an hour later, with teenage compatriot Nicolo Zaniolo providing two assists.
Atalanta fought back with Zapata heading just wide before Roma doubled their lead against the run of play with Steven Nzonzi finding a way through for Dzeko to finish off.
Zaniolo set up El Shaarawy to make it 3-0 five minutes before the break but Timothy Castagne headed Atalanta back into the game before the interval.
Di Francesco's men struggled after the break with former Roma defender Rafael Toloi nodding in Atalanta's second just before the hour off a Papu Gomez cross.
Zapata missed a chance for a third ten minutes later sending a penalty kick over the bar.
But a minute later he fired in his 14th goal in the last eight league games, for a total of 15 this season.
Both sides also drew 3-3 when they met in Rome last August, a game in which the Romans had come from 3-1 down.
Atalanta are now eighth, three points off the elite European places.