Frattesi late show pushes Inter close to title glory
Italy midfielder Frattesi poked home the decisive goal in the fifth minute of stoppage time in Udine to maintain Inter's 14-point lead at the top of the table with seven matches left in the season.
Inter looked to be heading for a draw as they toiled to add to Hakan Calhanoglu's penalty, scored nine minutes after half-time, which levelled Lazar Samardzic's freak deflected opener for Udinese.
AC Milan are Inter's closest challengers and Monday's win ensured that the champions-elect could seal their 20th Scudetto in a hotly-anticipated derby with their local rivals in a fortnight's time.
"We absolutely don't think we've won it yet. We have other matches to play and we need to go out and get it," said Frattesi to Sky Sport.
Inter are not playing with the same flair as they did before being knocked out of the Champions League by Atletico Madrid but they gritted their teeth to come from behind at the Bluenergy Stadium.
Simone Inzaghi's side not only have the chance to win the title in the Milan derby but can also beat the single-season points record of 102 set by Juventus in 2014.
On 82 points, Inter need to win all of their remaining seven matches to take their total for this campaign to 103.
"I'm really happy, it's a really big win towards we need to do," added Frattesi.
"You can't win every match 4-0, it's important that you also manage to win the tough matches."
Samardzic's goal came towards the end of a first half in which Inter went close to scoring three times only to be denied by super saves from Maduka Okoye.
Nigeria goalkeeper Okoye twice denied Calhanoglu from opening the scoring with fine efforts from distance before Samardzic gave the hosts a shock lead.
And Okoye pulled off another stunning stop two minutes after his team went ahead, stretching to his left to keep out Lautaro Martinez's thumping goal-bound header.
Inter were further frustrated again right after the break when Carlos Augusto's close-range finish was ruled out for offside but not long afterwards Okoye was penalised for crashing into Marcus Thuram and gave away the spot-kick from which Calhanoglu levelled.
The away side dominated the ball but barely threatened until deep into added time, when Frattesi struck the killer blow.
Frattesi was in the right place at the right time after Lautaro Martinez's rasping shot was pushed onto the post by Okoye, forcing home his seventh and most important goal of the season.