BERLIN (AP) — Robert Lewandowski helped Bayern Munich win at Borussia Dortmund 3-1 to throw his former side into more turmoil on Saturday with its third defeat in four Bundesliga games without a win.

Bayern moved six points clear of Dortmund, which previously led the league after making its best-ever start, and stayed four points above Leipzig after extending Jupp Heynckes' record to seven wins from seven games across all competitions.

Bayern had been five points behind Dortmund last month before Heynckes returned to take over from the sacked Carlo Ancelotti for his fourth stint in charge.

"We've worked brilliantly in the last 4 1/2 weeks," Heynckes said.

He led Bayern to the treble in 2013 and hasn't lost his last 29 Bundesliga games as coach.

Bayern defender Mats Hummels said of his former side: "Dortmund had opportunities."

Dortmund started aggressively in an attempt to disrupt Bayern, but there was little it could do to stop Arjen Robben scoring in the 17th.

James Rodriguez controlled Thiago Alcantara's cross on his chest and laid the ball back for Robben to cut inside and fire it into the top left corner. It was the Dutch winger's 93rd Bundesliga goal, making him Bayern's highest scoring foreigner.

Lewandowski finally scored with his heel from Joshua Kimmich's cross. Julian Weigl's deflection gave Dortmund 'keeper Roman Buerki no chance.

Lewandowski turned provider for the third as he distracted two defenders to help David Alaba decide the game.

Marc Bartra scored a consolation of sorts for Dortmund in the 88th minute.

GERMANY'S NEW STAR

Hamburger SV placed its hopes in 17-year-old Jann-Fiete Arp and was rewarded when he sealed a 3-1 win over Stuttgart.

Arp was given his first league start after scoring on his second appearance as a substitute in Hamburg's 2-1 defeat at Hertha Berlin last weekend. The Germany Under-17 captain responded by eluding two Stuttgart defenders and scoring in off the post with 20 minutes remaining.

Arp's rise could be bad news for Bobby Wood. The United States forward, who has only one goal in nine appearances this season, remained on the bench.

WHERE'S THE BALL?

Mainz goalkeeper Robin Zentner was teased by teammates after an awkward incident in the 1-1 draw at Borussia Moenchengladbach.

Zentner went to kick the ball in the first half — and found it was no longer there.

Abdou Diallo had already put the visitors in front when Zentner controlled a routine back pass with his right boot. He glanced forward to assess his options, while going to kick the ball one way and then another, only to look down in surprise when he kicked air — the ball had rolled away.

'Gladbach's Lars Stindl raced him for the ball but the goalkeeper managed to recover in time.

LEIPZIG GOES SECOND

Timo Werner struck late for Leipzig to come from behind and beat visiting Hannover 2-1 to move to second.

Daniel Caligiuri's second-half strike was enough for Schalke to beat his former club Freiburg 1-0 and go fourth. Freiburg coach Christian Streich was accidentally bundled over by one of his own players in the first half, when his side twice hit the crossbar.

Also, Bayer Leverkusen drew at Augsburg 1-1.