Milan lost the first-leg of their round 16 tie 2-0 at the San Siro.
"Some incidents proved costly, but we had started quite well. We conceded two stupid goals and threw away the first leg," the defender told Sky Sport Italia.
“We'll give it our best in the second leg, as we've got nothing to lose at this point. We gave our all today, but made costly mistakes on the two goals.
“It's difficult, but we'll have to try in London."