Argentina's World Cup winner Exequiel Palacios struck twice from the spot as Bayer Leverkusen blew the Bundesliga title race wide open with a shock 2-1 win over Bayern Munich on Sunday. 

With a little help from VAR, Leverkusen came from behind to hand coach Xabi Alonso a famous win on his first reunion with former club Bayern and keep the champions from regaining top spot.

Bayern are now a point behind leaders Borussia Dortmund, with the two sides set to meet in the next round of games on April 1.

"We are not in the position we hoped to be in going into that game," Bayern forward Thomas Mueller told Dazn.

"We deserved to lose today. Leverkusen had more bite to them and were very good against the ball," he added.

The champions survived an early chance from Jeremie Frimpong before taking the lead themselves when Odilon Kossounou deflected a Joshua Kimmich shot into his own net. 

The hosts continued to cause Bayern problems, however, and they fully deserved their equaliser from the penalty spot on 55 minutes.

Amine Adli was initially booked for diving after he was clipped by Benjamin Pavard, but the decision was reversed by VAR and Palacios converted from the spot. 

The same scene repeated itself 20 minutes later as Adli was brought down by Dayot Upamecano just inside the penalty area.

Once again, he was booked for diving, and once again, Palacios smashed the ball into the bottom corner after the intervention of VAR. 

The win also kept Leverkusen afloat in the race for Europe, with Alonso's side now just three points adrift of sixth. 

- Union bounce back - 

Elsewhere, Union Berlin gave their Champions League hopes a boost as a rare goal from Rani Khedira helped them to a 2-0 win over Bundesliga top-six rivals Eintracht Frankfurt. 

Khedira - the brother of 2014 World Cup winner Sami - stabbed in the opener to score only his seventh goal in 194 Bundesliga appearances and lift Union back into third place. 

"It's also my first goal for Union so I am very happy," Khedira told Dazn. "Today was much more about mentality than about tactics."

Both sides came into the game on five-game winless runs and trying to bounce back after being dumped out of European competition in midweek. 

Frankfurt had the lion's share of the chances in the first half as Union reverted to their trademark counter-attacking style. 

Randal Kolo Muani grazed the woodwork three times with headers, while Daichi Kamada forced a smart save from in-form Union keeper Frederik Ronnow.  

Yet the hosts struck first, as Khedira stabbed the ball home from close range after Frankfurt failed to clear a corner.  

Sheraldo Becker nutmegged Frankfurt keeper Kevin Trapp to find the net again for Union on 69 minutes, but the strike was ruled out for offside.  

Trapp was left blushing when he again let the ball through his legs a few minutes later to allow Kevin Behrens to double the lead.

Union -- unbeaten in 18 straight home games in the league -- are three points ahead of RB Leipzig in third.