Bayern Munich are making short work of the Champions League group stage, the German giants aware that a home victory over Roma on Wednesday will advance them to the knockout round with two games to spare. The Bavarians, who recorded their biggest away win in the competition when they crushed Roma 7-1 in the Italian capital last month, are in scintillating form and top Group E on a maximum nine points from three games. The German champions have won 12 of 15 games in the Bundesliga, German Cup and Champions League this season, drawing the other three matches to remain unbeaten in all competitions. They received a further boost to their confidence on Saturday when they came from a goal down to edge past fellow Champions League club and main domestic rivals Borussia Dortmund 2-1. More pleasing for Bayern coach Pep Guardiola was the performances of Arjen Robben, back from a minor knock, and fellow winger Franck Ribery, who is gradually returning to his best form after a long injury break. Dutchman Robben was a constant source of danger and also converted an 85th minute spot kick, awarded after Frenchman Ribery was brought down following a surging run, for the winner. "We are playing good football at times but there is still room for improvement," Robben said. "We won in Rome 7-1 and we beat Dortmund. "But we always have to remain critical, improve things, never let off and think that it will just happen by itself. It does not but we are on a good path." TITLE DEFENCE It is difficult to see how Bayern can improve on current form as they march towards their seventh straight knockout stage in Europe's premier club competition. In their three group games so far, they have netted nine times and let in just one goal. In the league they are equally as effective, scoring a staggering 23 goals and conceding three in 10 matches as they plot a smooth course towards a successful Bundesliga title defence. Roma had a far less successful weekend, slumping to a 2-0 defeat at Napoli to slip three points behind rivals Juventus at the top of Serie A. Coach Rudi Garcia knows his team have a mountain to climb at the Allianz Arena on Wednesday if they are to maintain their challenge for second place ahead of Manchester City, who are two points behind them after three matches. Roma have managed at least one away win in each of their last four Champions League group stage appearances and there would be no better time for a victory on the road to restore some pride after their thrashing at the hands of the Germans.