Romelu Lukaku was left frustrated after Inter Milan's 2-2 draw with Champions League opponents Borussia Monchengladbach.
Lukaku struck for the Nerazzurri - including in the 90th minute.
“This is not a good result in my view, because we can do better. We must keep working and be stronger mentally, because it's not an easy moment for us and we have to keep believing in our quality," Lukaku told Sky Sport Italia.
“Now we need to be stronger, above all mentally, and do better in defence, as we conceded two goals due to our errors. We made so many mistakes and wasted chances upfront too, so if we don't take those, we are made to pay at this level."