Kiessling's 70th-minute header flew wide of Koen Casteels' right-hand post during the Bundesliga fixture on Friday, but the ball ended up in the back of the net after appearing to go through a hole in the side netting.

The goal was awarded by referee Felix Brych despite Kiessling struggling to understand how the ball ended up in the net, and proved decisive as it gave Leverkusen a 2-0 lead in a game they eventually won 2-1. 

And Kiessling has now apologised to fans on his official Facebook page, admitting the goal should not have stood.

"Dear fans, friends and all those who just write to me," Kiessling wrote. "I can understand the reactions of many of you one hundred per cent and am myself quite upset.

"According to the reps (repeats) on TV I see it so clearly: it was not a regular goal. In the game I have not exactly seen in my header and the turning of the head, whether the ball went into the goal correctly or not.

"Somehow the ball was in the goal. Exactly what I told the referee.

"I'm sorry for all sports fans and the course of the game. To win so of course is not good. Fairness is important for the sport in our club and for me personally."

The win moved Leverkusen to the top of the Bundesliga table, although Hoffenheim coach Markus Gisdol has called for the match to be replayed.