Balotelli won a last minute penalty to rescue a point for Milan in their 1-1 draw.
"With Balotelli you know he can score from scratch and create theatre. That cost us two points," slammed De Boer after the 1-1 draw.
"This point comes with a bitter taste. At the end of the day I can live with a point, but to concede with the penalty was disappointing. There are always moments of contact in the box. It's about letting go at the right moment and Van Der Hoorn did that. It was ridiculous that penalty was awarded.
"We dominated the first half with very good positional play and also had our chances. After the break we made more wrong choices and were restless. Milan were more in the game.
"If you create three or four good chances in today's football, you must score at least one."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball