Inter missed the chance to significantly strengthen their grip on a Champions League place as a stoppage-time equaliser saw them held to a 1-1 draw at Serie A's bottom club Chievo.
Luciano Spalletti's men were presented with an opportunity to increase the gap between themselves and fifth-placed AC Milan, who were beaten 1-0 at home by Fiorentina earlier on Saturday.
The visitors were never at their best, but looked set to claim all three points thanks to Ivan Perisic's close-range 39th-minute strike, which marked his first league goal since September.
However, a Chievo side that offered scant resistance provided a late sting in the tail thanks to Sergio Pellissier as the captain dinked over Samir Handanovic, meaning third-placed Inter are just six points clear of Milan in the fifth.
Chievo forced Handanovic into action in the first minute, the Inter goalkeeper dealing with an awkward bounce after Riccardo Meggiorini let fly with a long-range volley.
Inter slowly took control of the game and only a fine reaction save from Stefano Sorrentino prevented him from turning home Danilo D'Ambrosio's left-wing cross.
Mauro Icardi and D'Ambrosio were involved as Inter broke the deadlock, though, combining down the left to set up Perisic to lash Inter into a lead that should have been doubled when Joao Mario shot wide from the Croatia international's low delivery.
Excellent build-up between Perisic and Icardi ended with the latter thwarted again by Sorrentino at the near post before a rare threatening Chievo attack saw Handanovic brilliantly turn Pellissier's effort behind.
It was Perisic who appeared the most likely to add to Inter's tally in a game that always looked in hand, but his inability to do so proved costly as Mariusz Stepinski headed on for Pellissier to earn Chievo's fifth point of a miserable season.
What does it mean? Inferior foe again troubles Inter
An inability to beat inferior opposition was Inter's undoing in the Champions League as a 1-1 draw with PSV saw them knocked out, and that failing reared its head again as their defence was breached at the last. Worryingly for Spalletti, who saw penalty claims for a challenge on Borja Valero rejected by VAR late on, a much tougher test lies in wait.
D'Ambrosio a delight
Inter's main threat came down the left from full-back D'Ambrosio, whose lack of a test defensively gave him the freedom to create the opener and set Icardi up for his first-half chance, which would have been decisive had it been taken.
Joao Mario makes a meal of it
Joao Mario had to stretch to meet Perisic's centre on the stroke of half-time, but he still had the goal at his mercy from close range and should have found the net. Instead, his miss was one of many chances Inter will reflect on after dropping points to Serie A's worst team.
What's next?
An enticing and crucial clash awaits Inter at San Siro on Wednesday when Napoli are the visitors. Chievo travel to take on Sampdoria on the same day.
