Liverpool-bound Naby Keita was sent off for the fourth time this season as 10-man RB Leipzig crashed to a shock 3-0 Bundesliga defeat to Mainz on Sunday.
Keita, who will join Liverpool in the summer, was shown a yellow card, then a red in quick succession late on for fouling Mainz scorers Alexandru Maxim and Bote Baku.
"That was completely unnecessary," Leipzig's captain Willi Orban fumed about Keita's dismissal.
The 23-year-old Keita stormed off the pitch and will be suspended for Saturday's home match against Wolfsburg.
It was the defensive midfielder's third expulsion for Leipzig in 2017/18.
He was also sent off for Guinea in a World Cup qualifier against Tunisia, the first of two red cards he earned last October before being dismissed in Leipzig's German Cup defeat to Bayern Munich.
This was Leipzig's fifth game without a win and leaves them sixth in the table, just hanging on to a Europa League berth.
Mainz boosted their survival hopes as Maxim and Baku hit late goals after Pablo de Blasis netted a first-half penalty.
Victory lifted Mainz out of the bottom three and into 14th with a three-point buffer from the relegation places.
Wolfsburg replaced them in 16th, which carries a two-legged play-off at the end of the season against the team which finishes third in the second division.
Mainz took the lead against the run of play when de Blasis converted a penalty on 29 minutes.
The hosts were awarded the spot-kick after Japan striker Yoshinori Muto was sent tumbling in the area.
Mainz kept pushing and deservedly went 2-0 up five minutes from time.
- Dortmund held by Bremen -
Moments after coming off the bench, Romanian midfielder Maxim fired home when the ball landed at his feet from a cross.
The fairytale win was complete when Baku, 20, who has risen up through the ranks from the club's Under-10 team, scored on his debut.
The midfielder outsprinted Leipzig defender Dayot Upamecano to fire home in the 90th minute to the delight of the Mainz bench.
"That was unbelievable," said Baku after his dream debut. "It couldn't have gone better for me."
The win does not guarantee Mainz's survival, but is a big help with matches against Borussia Dortmund and Werder Bremen to come.
Dortmund later squandered the chance to go second when they were held to a 1-1 draw at Werder Bremen.
Marco Reus continued to boost his chances of going to the World Cup with Germany by netting his sixth goal since February after overcoming a serious knee injury.
The winger fired Dortmund ahead with a well-placed shot on 19 minutes.
However, sloppy Dortmund defending allowed Danish midfielder Thomas Delaney to head Bremen level just before half-time.
Dortmund had the ball in the Bremen net with an hour played, but Omer Toprak's effort was ruled offside.
Borussia wasted two great chances to grab the winner to leapfrog Schalke into second.
Andre Schuerrle had a shot blocked by Bremen goalkeeper Jiri Pavlenka before English youth international Jadon Sancho hit the crossbar.
Then Schuerrle, a second-half replacement for Christian Pulisic, headed Sancho's perfect cross straight at Pavlenka just before the final whistle.
"That was a world-class performance. He deserves great respect," Reus said after Pavlenka valiantly protected Bremen's point.
"I certainly hope to be on the plane," added Reus about his World Cup chances having missed the Brazil 2014 triumph with an ankle injury.
Mainz midfielder Bote Baku added to Leipzig's woes by scoring on his debut to seal a precious 3-0 Bundesliga win for the hosts on Sunday