Five observations from the weekend's Bundesliga action

Bayern kept their 18-point lead in the table with a 2-1 victory over Schalke as Lewandowski and Thomas Mueller netted superb first-half goals with head coach Heynckes, 72, watching at home on Saturday.

Michy Batshuayi, on loan from Chelsea, now has three goals in two games for Borussia Dortmund after netting again in Saturday's 2-0 win over Hamburg and the Belgian says there is more to come.

Here are five things we learned from this weekend's Bundesliga action.

- It's tough on Bayern's bench - 

"Congratulations on winning," Heynckes texted to his assistant Peter Hermann, Bayern's acting head coach, after victory against Schalke at the Allianz Arena that was Bayern's 21st win in 22 games since he took charge, but Hermann can barely wait for his boss to return.

"It was a bit different than being an assistant coach. There is only one thing at Bayern: winning. The spot on the bench is too big for me," joked Hermann.

- Lewandowski sets records - 

Lewandowski now has 26 goals in all competitions after netting in all of Bayern's league games at the Allianz Arena this season, equalling Heynckes' record, set in 1972/73 for Borussia Moenchengladbach.

It marked a bumper weekend for Lewandowski, 29, who has been voted Poland's player of the year for the seventh straight occasion.

If he scores against Hertha Berlin at home on February 24 he will claim the out-right record.

- 'Batsman' begins, Reus returns -

Michy Batshuayi, on loan from Chelsea, netted his third goal in two games on his Dortmund home debut, then tweeted a picture of his somersault celebration with the text "Batsman begins".

Batshuayi tapped home a Christian Pulisic speculative shot on 49 minutes for his first goal at Signal Iduna Park before Mario Goetze made it 2-0 in added time.

"Our game will just keep getting better," said Batshuayi.

"I am going to watch the game on DVD to get even better for Bergamo on Thursday (in the Europa League)."

Germany winger Marco Reus also played his first Dortmund games after 259 days out after tearing a knee ligament.

- Red-faced Jarstein - 

Goalkeeper Rune Jarstein needed a crash-course in the rules after blundering in Hertha Berlin's shock 2-0 win at Bayer Leverkusen.

With Berlin 2-0 up, Hertha's shot-stopper Jarstein conceded a free-kick seven metres from his own goal after letting the ball bounce off his hands, then picked it up.

"I didn't hold the ball, just touched it. I have been doing that my whole life long and the ref never blew before," he said.

"I have even done it this season, but now I know the rules."

Luckily for the Norwegian, Leverkusen's Jamaica winger Leon Bailey twice had shots blocked while Kevin Volland hit the crossbar from the indirect free-kick.

- Russ celebrates recovery - 

Defender Marco Russ scored in Eintracht Frankfurt's 4-2 thrashing of bottom side Cologne on Saturday -- his first goal since overcoming testicular cancer, which was discovered by a drugs test in April 2016.

After surgery and chemotherapy, Russ played again in the German Cup last February, then spent the rest of 2016/17 building up fitness.

Home fans cheered when Russ smashed home his header as Frankfurt scored twice inside two minutes to floor Cologne.

Eintracht are fourth and on course for a Champions League spots next season.

"The longer we stay up near the top, the greater the hope that at the end we can have an international place," said Russ.