South Korea forward Son led Leverkusen to a 5-3 win over Hamburg SV which pulled them level on points with second-placed Dortmund after a match featuring some calamitous defending from both teams as well as superb finishing.
Dortmund, beaten 1-0 at home by Arsenal in the Champions League on Wednesday, were sunk by a superb Ivica Olic strike in their 2-1 defeat at Wolfsburg as last season's runners-up showed worrying signs of a slump.
Bayern Munich beat Augsburg 3-0 to set a new Bundesliga record by completing their 37th match without defeat as they went further ahead at the top after their seventh straight home win of the season.
Last season's treble winners, who overhauled the record set by Hamburg 30 years ago, have not been beaten in the league since October 28 last year when they lost 2-1 at Bayer Leverkusen.
Bayern, who have 32 points from 12 games, moved four points clear of Dortmund who are now level on 28 points with Leverkusen.
Dortmund went ahead in first-half stoppage time with a Marco Reus free kick.
In a thrilling second half, Ricardo Rodriguez equalised for the Wolves from a free kick before Olic scored the winner with a superb curling effort while Dortmund striker Robert Lewandowski had two penalty appeals turned down.
"It was a game with, let's say, lots of players on the floor and lots of free kicks. In some situations, everything went against us," said Dortmund coach Juergen Klopp. "They could have given us one of the two penalties."
Unheralded Leverkusen suggested they could be Bayern's biggest challengers this season after winning an eight-goal humdinger against former Netherlands coach Bert van Marwijk's Hamburg.
Son, who joined Leverkusen from Hamburg this season, scored two superbly-taken goals in the first 16 minutes, Maximilian Beister pulled one back for Hamburg and Pierre-Michael Lasogga levelled in the 50th minute.
Son put Sami Hyppia's Leverkusen back in front five minutes later with another coolly-taken goal and set up a fourth for Stefan Kiessling to extend Leverkusen's lead after Hamburg gave the ball away.
Lasogga pulled another back, his eighth of the season, after Son had lost possession near the corner flag, but Gonzalo Castro wrapped up the game in the 89th minute by chipping the ball over Rene Adler after Hamburg were again caught on the break.
"We lost this game through our own mistakes," said van Marwijk, who put his head in his hands in exasperation after the last two Leverkusen goals.
There was no such drama in Munich where Bayern, treble winners last season, cruised to a typically straightforward home win.
Jerome Boateng put them ahead after five minutes and Franck Ribery ended the game as a contest when he scored with a rasping free kick just before halftime. Thomas Mueller rounded off the win with a last-minute penalty.
"The early goal made it easier but we didn't play so well," coach Pep Guardiola told Bayern's website. "In the second half, we got better and created some chances. I hope that the players return fit after the international break."
Jefferson Farfan netted the other for Schalke as they restored some form following the 3-0 midweek defeat to Chelsea in the Champions League.
Hoffenheim, who have scored 28 and conceded 28 goals in 12 games, were involved in another goal feast but lost 3-2 at home to Hertha Berlin.
Anis Ben-Hatira and Ramos struck to give Hertha a 2-0 lead before Hoffenheim replied with a penalty and free kick converted by Sejad Salihovic, only for Ramos to head the winner six minutes from time.
The Bundesliga was hit by another ball-over-the-line controversy in the day’s late kick-off after Nuremberg had a goal disallowed in their 3-1 defeat at Borussia Moenchengladbach.
Bottom-of-the-table Nuremberg, the only Bundesliga team without a win this season, were trailing 2-1 when a shot by striker Josip Drmic hit the underside of the crossbar and bounced down on to the line and out of the goal.
The referee waved play on and even slow-motion replays were inconclusive as to whether the ball had fully crossed the line or not.
Last month, Bayer Leverkusen won 2-1 at Hoffenheim thanks to a "phantom goal" which was awarded after Stefan Kiessling's header clearly went into the side-netting.