AC Milan were held to a second successive goalless draw in the Champions League at Borussia Dortmund on Wednesday to slip to third in Group F.
Stefano Pioli's Italian side, semi-finalists last season, created the better chances but failed to convert them, just as in their opening 0-0 draw with Newcastle at the San Siro.
"I'm disappointed," Milan winger Rafael Leao told Prime Video.
"We can't be happy with this draw, we missed too many chances and in the Champions League that's unforgivable."
Dortmund drop to the bottom of the early standings, one point behind Milan and three adrift of early leaders Newcastle after their 4-1 victory over second-placed Paris Saint-Germain.
The Germans are also yet to score in the competition this term after losing 2-0 to PSG at the Parc des Princes.
"We played some great football in my opinion," Dortmund striker Niclas Fuellkrug told DAZN.
"It (Newcastle beating PSG) can give us confidence and we can see that anything is possible in this group, no team should be counted out."
Donyell Malen shot wide twice early on while Julian Brandt hooked an overhead effort over the crossbar as Dortmund started strongly.
But the best chance of the first half fell to the visitors in the 37th minute, as a stretching Olivier Giroud pounced on a loose ball but could only steer his close-range shot over the bar.
Milan pushed for a winner in the second half, with Theo Hernandez heading an excellent opportunity wide eight minutes from time.
Away midfielder Tijjani Reijnders came even closer in the 87th minute, curling narrowly off target as the visitors were forced to settle for a point.
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