Sunderland 1-0 Liverpool, video ballooned goal by Darren Brent

Liverpool lost 1-0 against Sunderland due to an incredible "ballooned" goal. In the minute 4 Sunderland's Darren Brent scored in Reina's net after the ball was deviated by a... balloon. As seen in the video, the situation clearly hindered Reina but the goal was validated despite that normally by sport law such a goal should be canceled.
Video Darren Brent's balloon deviated goal against Liverpool (video Sunderland-Liverpool 1-0)