Borussia Dortmund slumped to a fourth consecutive away defeat on Saturday, losing 3-1 to Mainz after Emre Can's first-half sending-off.
Dortmund, who had a midweek confidence boost with a 1-0 home win over Sturm Graz in the Champions League, struggled against the hosts and were left with 10 men in the 27th minute when their captain launched a reckless studs-up challenge on Lee Jae-Sung and received a straight red card.
Things got even worse when the South Korean rose to nod a deft finish past Alexander Meyer to give Mainz the lead in the 36th minute.
However, Lee then brought down Serhou Guirassy in the box just four minutes later, with the striker restoring parity from 12 yards.
Dortmund could not hold on until half-time though, as their defence was again caught out when Jonathan Burkardt turned in a cutback in first-half stoppage time.
After the break, Mainz picked up where they had left off, bagging a third goal through Paul Nebel, who coolly slid in from the edge of the six-yard box in the 54th minute.
Dortmund, who have lost four of their five away league games this season and drawn the other, are on 16 points in seventh spot. Mainz are three points behind in 10th.
Data Debrief: Away day woes
Dortmund have won just one of their away games in all competitions this season - a 3-0 victory over Club Brugge in the Champions League - but there does not seem to be an end in sight to their troubles.
It is the first time that Dortmund have lost six competitive away games on the bounce since 2006-07, but Nuri Sahin's bigger worry will be the fact that they only attempted two shots, with their penalty the only effort on target.
Meanwhile, Mainz have ended a three-match winless run in the Bundesliga, extending their impressive recent record against Dortmund in the process, as they are unbeaten in four games against the Black and Yellow (W2 D2).