Inter snatched a point from Czech giants Slavia Praha in their Champions League group stage opener thanks to a strike from substitute Nicolò Barella in added time.
Sitting in one of the tightest groups in the competition with Barcelona and Borussia Dortmund, Stefan de Vrij and Danilo D'Ambrosio wasted golden chances to put Inter into an early lead, although it still highlighted a potential weakness that Slavia Praha had from set-pieces.
Samir Handanović just avoided being left with egg on his face by conceding the opening goal while trying to play out from the back, but he was helpless to stop striker Peter Olayinka putting the visitors into a shock lead from close range after half-time.
Inter then snatched a point from the match in added time after Stefano Sensi's free-kick rebounded back to Barella, who mishit a volley into the far corner of the net in his first-ever appearance in European competitions.
Key Talking Point
Antonio Conte will be all too aware that his side won't be able to control every minute of every match this season, but Inter's slow start highlighted the fact that they are only three games into their campaign - compared to Slavia Praha, who have played nine league matches.
The Nerazzurri had better options in each position than Tuesday's opposition, but as a collective, Inter didn't show any signs as to why they're being tipped as a team who could topple Juventus in Italian football's hierarchy this season.
There seemed to be a severe lack of confidence in defence which gave Slavia Praha's attacking players confidence as the match went on, but it was Inter's crippling deficiency of creativity in the final third which proved to be most telling at San Siro.
In the end, a mishit volley from substitute Barella saved Inter from an opening day defeat, but Inter are now walking on thin ice if they want to make it through Group F unless their performances improve drastically over the next few weeks.
Starting XI: Handanovic (5); D'Ambrosio (5), de Vrij (6), Skriniar (7); Candreva (4), Gagliardini (6), Brozovic (5), Sensi (7), Asamoah (6); Lukaku (6), Martinez (7*).
Substitutes: Lazaro (6), Barella (4), Politano (6).
We're clutching at straws Inter struggled to create anything of note for large chunks of the match, but striker Lautaro Martínez brought the hosts' toothless attacking lineup an important chunk of South American bite.
Although the Argentina international wasn't able to create any chances for himself, Martínez was the only Inter player who looked to press Slavia Praha's defenders and he even forced the visitors into the odd mistake.
Starting XI: Kolar (5); Coufal (6), Kudela (5), Hovorka (6), Boril (7); Soucek (6), Traore (6), Husbauer (7); Masopust (6), Stanciu (7), Olayinka (8).
Substitutes: Zeleny (7), Provod (6), Helal (6).
Inter might have got over their first hurdle in Europe, but the Serie A fixture schedule is now set to turn ugly for the Nerazzurri as they race rivals Milan, as well as Lazio, Sampdoria and Juventus in their next batch of fixtures.
Conte's side will also have to travel to Barcelona on matchday two in the Champions League, just before they host Italian champions Juventus.