The Bavarians currently hold a 17-point lead at the top of the Bundesliga, and have all but sealed a place in the last eight of the Champions League with a 3-1 away victory over Arenal in the round-of-16 first leg.
"[Wednesday] was a very intense game with a deserved winner in Bayern. This season, Dortmund are too small for FCB, and with the form they showed on Wednesday, the treble for Bayern is no illusion," he wrote in his column for TZ.
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"These two teams will come to dominate German football. Through the last two league titles, they [Dortmund] have incited Bayern to improve. This is a positive rivalry that will make both teams better."
Bayern have been heavily linked with a move for striker Robert Lewandowski, who will not extend his current Dortmund contract.
Although Franz Beckenbauer claimed Bayern do not need to sign Lewandowski due to the forward options already at their disposal, Roth insists that the club cannot have too many players of such a calibre.
"When the calibre of Lewandowski is on the market, then you have to strike," he added.
"I do not believe [Mario] Mandzukic and [Mario] Gomez will be around forever. My opinion, you cannot have too much quality at this level."