BERLIN : Union Berlin stumbled to a goalless draw against visitors Cologne on Saturday, losing further ground in the Bundesliga race with their third consecutive league game without a win.The hosts were toothless throughout and had Frederik Ronnow to thank for rescuing a point, with the keeper making three superb one-handed saves in the second half to stop Cologne.Union, who won the first five league matches of the year but have now managed just two points from the last three, rarely broke through the visitors' tight defence.When they did come near the box though they were let down by their poor passing and sloppy finish.Union are still in third place on 44 points, with Bayern Munich, in second on 46, facing VfB Stuttgart later on Saturday.Borussia Dortmund are in top spot on 49 following Friday's 2-1 win over fourth-placed RB Leipzig.