Berlin (AFP) - Thomas Mueller said he was stunned that his Bayern Munich team had reined in Bundesliga leaders Borussia Dortmund whose nine-point lead has evaporated.
Bayern moved level on points with Dortmund on Saturday after a 5-1 thrashing of Borussia Moenchengladbach.
Dortmund, meanwhile, had stumbled to a shock 2-1 defeat at Augsburg on Friday.
"It was a good day for us. I can't remember the last time we won by such a margin at Moenchengladbach," Mueller told Sky.
"We didn't think we would catch Dortmund up so early. We are better now than we were last autumn and want to continue."
This was Bayern's 11th win in 12 league games, a run which has allowed them to erode the nine-point lead Dortmund held in December with only a goal difference of two now separating the sides, both on 54 points.
Despite illness and injury hitting their squad, Bayern needed just two minutes to take the lead when Martinez headed home from a corner.
Mueller made it 2-0 after 11 minutes by tapping home a Gnabry cross.
Gladbach briefly rallied when their captain Lars Stindl pulled a goal back eight minutes from the break, but Lewandowski made sure of the win after he converted Thiago Alcantara's pass to smash the ball home on 47 minutes.
Gnabry added Bayern's fourth before Lewandowski netted a late penalty for his 195th Bundesliga goal -- making him the league's joint top-scoring foreign player alongside Werder Bremen's 40-year-old Peru striker Claudio Pizzaro.
The result avenged Bayern's shock 3-0 defeat to Gladbach in Munich last October.
"There was a score to settle from that game -- we had it at the back of our minds," admitted Bayern goalkeeper Manuel Neuer.
"Of course we are happy with a 5-1 win, but we aren't first, so we have to stay calm."
- Schalke crash again -
Earlier, Schalke crashed 4-0 at home to Fortuna Duesseldorf to increase pressure on head coach Domenico Tedesco, who insisted - "I'm not one to just piss off".
Director of sport Christian Heidel resigned after last weekend's 3-0 defeat at Mainz and the first job of his replacement Jochen Schneider, who starts work Tuesday, could be to sack Tedesco.
"The sports director has not started yet, he will say something on Tuesday," said Schalke chairman Clemens Toennies after defeat at the Veltins Arena left them 14th -- seven points from the relegation places.
Schalke face Manchester City away on March 12 in the Champions League last 16 looking to overturn a 3-2 defeat from the first leg, but Tedesco could be gone before then following their 13th defeat in 24 league games.
Duesseldorf ran riot as their Polish striker Dawid Kownacki scored his first two goals in only his third Bundesliga match.
Elsewhere, RB Leipzig squeezed past bottom side Nuremberg with a 1-0 away win to move up to third.
Leipzig knocked Gladbach down to fourth after surviving a first-half scare at Nuremberg, whose midfielder Hannes Behrens hit the crossbar with a penalty attempt before defender Lukas Klostermann scored RB's winnner from a corner.
Eintracht Frankfurt, who face Inter Milan in the last 16 of the Europa League on Thursday, moved up to fifth with a 3-2 win at home to ten-man Hoffenheim thanks to a headed 96th-minute goal by substitute striker Goncalo Paciencia.
The Portugal forward came on with 10 minutes left to break the hearts of Hoffenheim, who had been 2-1 up before playing the last 25 minutes with ten men after Ghana defender Kasim Adams received a second yellow card.
Frenchman Sebastian Haller headed Frankfurt level on 89 minutes before Paciencia's dramatic late winner.
Defender Niklas Stark made amends for an own goal just after the break against Mainz to net Hertha Berlin's winning goal in their 2-1 home victory after Marko Grujic, on loan from Liverpool, had equalised at the Olympic Stadium.
Bayer Leverkusen climbed to sixth, among the Europa League places, after running out 2-0 winners over mid-table Freiburg thanks to goals by Chile's Charles Aranguiz and Jamaica winger Leon Bailey.