Simone Inzaghi warned Inter Milan must show more "conviction and malice" after they slumped to a 2-1 Serie A defeat at relegation-threatened Spezia on Friday.
Bartlomiej Dragowski saved an early Lautaro Martinez penalty to set the tone for a miserable night for Nerazzurri, who failed to reduce runaway leaders Napoli's 15-point lead.
Daniel Maldini stunned Inter when the on-loan Milan attacking midfielder put Spezia in front just 10 minutes after being introduced as a half-time substitute.
Romelu Lukaku showed Martinez how it's done by equalising with a spot-kick after 83 minutes, but M'Bala Nzola gave Spezia a first win over Inter when he scored a penalty of his own four minutes later after Denzel Dumfries barged Viktor Kovalenko over.
Inter had 28 shots as they dominated much of the game, but slumped to an eighth Serie A defeat of the season as they prepare to take a 1-0 lead to Porto for a huge Champions League round-of-16 second leg on Tuesday.
Head coach Inzaghi knows the Nerazzurri only have themselves to blame.
He told DAZN: "It hurts, the defeat came in a different way than the others. We put everything on the field, perhaps we needed a little more malice.
"We have a duty to go ahead and I take responsibility for the defeat. We should have been more cynical, we come out stronger from defeats even if there have been more this year."
Six of Inter's eight Serie A defeat this season have come on their travels and Inzaghi says that must be addressed.
"It's a path that doesn't satisfy us away from San Siro, tonight we had to have more conviction and malice," he said.
"I don't believe in luck in football, luck must be sought,"
