Bayern Munich coach Jupp Heynckes rated the Bundesliga leaders\' performance as \"top class\" after they hammered Hanover 5-0 to extend their lead at the top of the table to nine points. \"It was a thoroughly deserved victory and we were top class, because we were very assertive and aggressive from the start. We kept it tighter than we have done recently,\" enthused Heynckes. \"We needed total concentration, especially in defence, but the team showed that brilliantly for 90 minutes.\" Bayern ran riot at the Allianz Arena and set another Bundesliga record of 34 points after the first 13 games while defending champions Borussia Dortmund moved up to second in the table with a 2-1 win at Mainz. Dortmund travel to face Bayern at Munich\'s Allianz Arena on Saturday in a key Bundesliga showdown. The hosts took the lead with only four minutes gone when Spain midfielder Javi Martinez netted his first goal since his August transfer from Athletic Bilbao. Germany midfielder Toni Kroos then doubled the Bavarians\' lead on 24 minutes then France wing Franck Ribery fired home on 37 minutes before Brazil centre-back Dante made it 4-0 when he met Kroos\' free-kick at the far post on 63 minutes. Germany striker Mario Gomez needed just 26 seconds to claim the fifth after coming off the bench on 67 minutes for his first Bayern goal in three months following ankle surgery. \"After such a long time with no football, it\'s a wonderful feeling to play and score again,\" he said. \"The goal was incredible, I was really elated, and I remembered how much football matters to me.\" Hanover coach Mirko Slomka could only rue his team\'s poor performance. \"These disastrous individual errors and such an early goal shouldn\'t be happening,\" he said. \"They ripped us to pieces at times. There was a real gulf in class for long spells, so congratulations to Bayern.\" Dortmund coach Jurgen Klopp was delighted as his team came from behind at Mainz to claim their third straight away win with a 2-1 victory. Mainz\'s Marco Caligiuri put the hosts ahead on four minutes, but Germany midfielder Marco Reus equalised when he hit the top corner from 17 metres out just eight minutes later. Dortmund went ahead just before the break when Mario Goetze put Poland striker Robert Lewandowski into space to flick the ball over the Mainz goalkeeper and claim the three points and wrest second place from Ruhr neighbours Schalke 04. \"I have to pay my team a huge compliment and I am delighted with the way they are playing,\" said Dortmund coach Jurgen Klopp, whose team face Bayern in Munich next Saturday. \"It was an incredibly intense game. It was a psychological test of our character and we passed it.\" Schalke dropped to third after drawing 1-1 with Eintracht Frankfurt, who are fourth, in Gelsenkirchen.