PORTO, Portugal (AP) — AC Milan is unbeaten in Serie A but can’t find a way to win in the Champions League. The Rossoneri were beaten 1-0 at Porto in Group B for their third straight defeat in the competition. Luis Díaz scored from the edge of the 18-yard box in the the 65th minute after hitting the post in the first half. Liverpool leads the group with a perfect nine points following a 3-2 win at Atletico Madrid in the other group match. Atletico and Porto have four points each and Milan has zero. It’s the first time that Milan has lost the first three matches in the group stage of the Champions League.