Inter secured Champions League qualification in the most dramatic fashion as Luciano Spalletti's men came from behind to beat 10-man Lazio 3-2 on Serie A's final day.
Lazio only needed to avoid defeat in what was effectively a play-off at the Stadio Olimpico on Sunday, but they collapsed incredibly in the closing stages as captain Senad Lulic was dismissed.
Ivan Perisic's remarkable own-goal, an Adam Marusic shot deflecting in off the midfielder's face, gave Lazio the lead, but Danilo D'Ambrosio levelled with an acrobatic effort from close range.
100 - Mauro Icardi scored tonight his 100th goal in Serie A for Inter, in 159 games played. Nerazzurro.— OptaPaolo (@OptaPaolo) May 20, 2018
Felipe Anderson's breakaway goal restored the lead and put Lazio in control at half-time, but the Nerazzurri somehow completed a stunning comeback with two goals in three minutes.
Referee Gianluca Rocchi had already changed his mind about one penalty for the visitors following a VAR review when he pointed to the spot after Stefan de Vrij - strongly rumoured to be joining Inter at the end of the season - hacked Mauco Icardi down in the box.
The Inter captain converted and, after Lulic was shown a second yellow card, Matias Vecino headed in Marcelo Brozovic's corner, Simone Inzaghi's men unable to muster a fightback of their own after the coach earlier made defensive changes to leave them fifth and devastated at the full-time whistle.