Jurgen Klopp's side were held to another Bundesliga stalemate ahead of the visit of Juventus in the Champions League this week
Borussia Dortmund's Bundesliga resurgence was kept in check as they were held to a 0-0 draw at home by Koln on Saturday.
Jurgen Klopp's side could have climbed to within a point of ninth-placed Werder Bremen, and the top half, with victory but they failed to break down Peter Stoger's well-drilled visitors.
It is Dortmund's second consecutive draw in the league, following four straight wins, and it could have been worse as the visitors fashioned the better chances.
Koln's deep defensive line succeeded in stifling the hosts' creative talents, as Stoger's men followed up their first victory since January with a hard-earned point that moves them six points clear of the bottom three.
Attention now turns to the Champions League for Klopp's side, as they host Juventus in the second leg of their last-16 tie on Wednesday, seeking to overturn a 2-1 deficit.
