Milan have not won in four games but will use their poor form as a stepping stone towards improvement, according to Stefano Pioli.
Franck Kessie and birthday boy Gianluigi Donnarumma were Milan's heroes as the Serie A giants edged out Red Star Belgrade on away goals.
Milan are four points adrift of Inter following their derby loss but Stefano Pioli sees a determined and willing group.
Gianluigi Donnarumma is out of contract at San Siro this off-season and Manchester United may have jumped the queue for him.
Lautaro Martinez menyatakan Inter menunjukkan warna sebenar mereka dalam kemenangan derby 3-0 semalam ke atas Milan di San Siro.
Stefano Pioli berkata Milan tidak lagi senang hanya memainkan peranan sebagai pencabar dalam perlumbaan gelaran Serie A dan akan bekerja keras untuk pulih daripada kekalahan kepada Inter.
Inter moved four points clear at the Serie A summit, with Christian Eriksen and Ivan Perisic playing leading roles.
Stefano Pioli is keen to ensure Milan's standards do not slip, calling for hard work after a third straight winless match.
Lautaro Martinez scored twice in Inter's win over Milan and the striker is determined for them to stay top until the end of the season.
Pre-match optimism from Milan appeared misplaced on Sunday as Inter convincingly won the derby to take charge of the Serie A title race.