BERLIN: Bayern Munich took another small step toward an unprecedented fourth successive Bundesliga title with a hard-fought scoreless draw at closest rival Borussia Dortmund on Saturday. Bayern, which had a healthy eight-point lead before Wednesday's shock home defeat to Mainz, preserved the five-point gap with nine games remaining. Bayern midfielder Arturo Vidal came closest to scoring for either side in the 65th minute when Dortmund 'keeper Roman Buerki produced a fine reflex save to deflect his shot onto the crossbar. The visitors had 16 efforts on goal, compared to Dortmund's 11. League top-scorer Robert Lewandowski was quiet on his return to his former club, while Pierre-Emerick Aubameyang was unable to seriously trouble Manuel Neuer at the other end. It was the first 0-0 draw in 26 competitive meetings between the rivals.