DUGOUT_
Former Milan attacker Junior Messias snatched a point for Genoa in the fifth minute of stoppage time after ramming home the leveller from his own saved spot-kick, given after Inter defender Yann Bisseck was penalised for a clumsy handball as he tried to head clear.
Bisseck's mistake cost Inter a win which looked to be have been secured by Marcus Thuram's goals in each half following Alessandro Vogliacco's shock early opener for hosts Genoa.
"We're disappointed because the boys put in a very professional performance," said Inter coach Simone Inzaghi. "We played very well in the first half and created plenty but conceded an unlucky goal... If you let in two goals like we did tonight then it becomes difficult to win matches.
"When a team like ours goes ahead when we did we cannot concede, especially not a goal like we did."
France forward Thuram thought he had won the game for Inter when with six minutes remaining he delicately dinked home Davide Frattesi's pass, a goal which was initially chalked off for offside but then given after a VAR check.
Thuram was Inter's most dangerous player as he also forced two super saves from Pierluigi Gollini and won a penalty in the 34th minute which was then revoked following a check on his clash with Milan Badelj.
The draw wasn't a just great result for Genoa because they were playing the reigning champions but also because Alberto Gilardino's team lost key players in the transfer window and have been hit with a wave of injuries.
Genoa have sold last season's attacking stars Mateo Retegui and Albert Gudmundsson and were without five players on Saturday, meaning Messias had to play up front rather than in his preferred wide position.
"The boys were really great tonight. With all the difficulties we've had, we knew how hard it would be but they reacted brilliantly," said Gilardino.