RB Leipzig were left to rue Dayot Upamecano's first-half dismissal as Christian Strohdiek's stoppage-time equaliser earned the Bundesliga's bottom side Paderborn a 1-1 draw.
Central defender Upamecano received two cautions prior to half-time, the second of which came after he kicked the ball away in anger.
However, it looked as though Leipzig were going to take all three points anyway, with Timo Werner having put all the talk of his reported move to Chelsea to one side to set up Patrik Schick's 27th-minute opener.
Yet Werner missed a late chance that would have made it 2-0 when he grazed the crossbar, and Strohdiek pounced to level after Marlon Ritter's effort was pushed into his path by goalkeeper Peter Gulacsi.
Prior to kick-off, Leipzig CEO Oliver Mintzlaff denied a £54million (€60m) deal that had been agreed for Chelsea to acquire Werner, who missed the chance to show why he was so highly rated by scuffing his shot from Dani Olmo's early cutback.
Julian Nagelsmann's side had scored 11 times in their previous three fixtures and it seemed like only a matter of time before they got the opener, though Werner was thwarted by a brilliant Uwe Hunemeier block.
However, Werner was released again down the left by Christopher Nkunku and he squared for Schick to apply a first-time finish.
It appeared like a straight-forward afternoon was in store but that changed when Upamecano was dismissed on the stroke of half time.
Booked earlier for a professional foul, the 21-year-old was frustrated at losing out to Streli Mamba, hacking away and pulling him back before petulantly kicking the ball away to earn a second caution.
That gave Paderborn hope at the start of the second half but it was still Leipzig who fashioned the better chances.
Olmo tested Leopold Zingerle with a low drive from a corner before Werner went past the keeper on a counter but failed to find the target from out wide.
Christopher Antwi-Adjei twice had a chance to level for Paderborn only to fire wide on both occasions and he then fluffed his lines again when under pressure from Tyler Adams in the box as he appealed for a penalty that was not given.
Werner should have scored his 26th of the season but his effort kissed the top of the crossbar and Strohdiek made him pay with an emphatic finish after Gulacsi could only divert Ritter's drive into his path.
What does it mean? A rare point for Paderborn, but Leipzig stay unbeaten
A top-four finish still looks on the cards for Leipzig, who are now unbeaten in 11, but the fact they have drawn a league-high 11 times is why a realistic title challenge has not materialised.
Paderborn's relegation will likely be confirmed in the coming weeks and this point will be welcomed by the basement dwellers, who have had little cause for cheer this term.
Chelsea talk not distracting Timo
A move to London may be in the offing, but there was no drop in commitment from Werner, even if it was not his day in front of goal.
He did produce an eighth Bundesliga assist of the season – one of a team-high four key passes he made during the game.
Day to forget for Dayot
Werner is not the only Leipzig player attracting attention from Europe's top clubs if the gossip columns are to be believed, though potential suitors would not have been impressed by Upamecano's performance here.
He got caught out with a ball over the top for his first booking and the second, when frustration took over as he kicked the ball away, was a real sign of naivety that cost his team.
Leipzig, who still have to play second-placed Borussia Dortmund, face Hoffenheim on Friday while Paderborn's relegation fate could be sealed if they lose to fellow strugglers Werder Bremen the following day.