The 2002 Bundesliga champions lie one point and three places above the relegation zone after losing 2-0 to fellow strugglers Bochum on Saturday.

"It is in the best interests of the future of BVB, therefore I have handed in my resignation," he explained.

Rober took over from Bert van Marwijk during the winter break and began in the best possible manner with a 3-2 home victory over Bayern Munich.

However, he has been able to win just one game since, and with six defeats out of eight games, has seen the club slide onto the brink of the relegation zone.

"After the defeat in Bochum, I realised that this team is a long way from realising how serious the situation is," said the 53-year-old former Wolfsburg and Partizan Belgrade coach.

The Dortmund players were blockaded inside the Ruhr Stadium by hundreds of angry fans in Bochum following the weekend derby defeat.

Rober admitted he was unsure what the future would hold, and within 48 hours, has made up his own mind.

"Individuals do not count in a situation like this," he added.

Dortmund now begin the desperate search for a man who can steer them away from the bottom three in the last eight games of the season.

It is believed that number one target Thomas von Heesen, who recently left Arminia Bielefeld, is no longer interested in taking over either now, or at the start of next season.

Whether the likes of Felix Magath, who was used to success at Bayern Munich, or Thomas Doll, who was fired with Hamburg in a similarly precarious situation two months ago, would be attracted to the challenge remains doubtful, though.