Schweinsteiger: Bayern better than Dortmund
He told Eurosport: "Dortmund have momentum. You can't say they are playing badly and they do have quality. But I am of the opinion that Bayern are a better team than Dortmund.
"They have managed to win their games while we have only drawn ours. We have dropped many points through carelessness and a lack of concentration. That should not happen to a team like Bayern Munich."
Dortmund also beat Bayern 2-0 when they met at the start of October. Schweinsteiger added: "I am convinced that so far (this season) no team has been better than us. Even the game in Dortmund...we should have settled it before the break. The only game where a draw would have been fair was against Mainz. The rest we could have won."
Dortmund's 2-0 win over Nuremberg on Sunday left them ten points clear at the top of the German league and 17 points ahead of Bayern. Munich's 2-0 defeat at Schalke on Saturday leaves them seventh in the table, but Schweinsteiger, 26, admitted Dortmund are playing some impressive football.
"They have their qualities, particularly in terms of their attacking play and they are also very aggressive."
Coach Louis van Gaal has already admitted his side may have lost the title race with more than five months left to play this season.
Schweinsteiger has a contract at Bayern until 2012, but the club are hoping he will sign an extension to the deal when the Bundesliga breaks for winter at the end of the month.