Inter midfielder Calhanoglu Hakan scored a penalty against his former club Milan, who missed out on an opportunity to go top of Serie A in a 1-1 derby draw at San Siro.
Calhanoglu, who joined Inter Milan from AC Milan on a free transfer in July, won and then converted an early spot-kick
Calhanoglu has become just the fourth player to score in his first Serie A Milan derby after having played the previous one with the opposing team in the three-points-for-a-win-era (since 1994-95).
The Turkey international joins the illustrious trio of Hernan Crespo, Ronaldo and Zlatan Ibrahimovic.
However, AC Milan equalized minutes later after Stefan de Vrij scored an own goal.
Inter was handed a second penalty in the first half, but Ciprian Tatarusanu saved Lautaro Martinez's strike from 12 yards to keep his side level.
Tatarusanu's penalty save made him the first Milan player to have saved a penalty in a Milan derby in Serie A since Opta started to collect this kind of data (2005-2006).
As for Inter Milan's striker Lauturo Martinez, this was his third missed penalty out of six past penalties he has taken in all competitions for Inter.
With the draws this meant that AC Milan have picked up 32 points in the opening 12 games of a Serie A season for their first time in the three-points-for-a-win era.
However, simply denying Milan three points meant the title-chasing AC Milan were unable to leapfrog Napoli, who also drew 1-1 with Hellas Verona.
After the international break Milan travel to face Fiorentina on November 20, while Inter will host Napoli the day after.
Ac Milan manager Stefano Pioli who won the Serie A Coach of the Month award for October was handed the award before the Milan-Inter game on Sunday.