MAINZ, Germany (Reuters) -Champions League competitors Borussia Dortmund slumped to a 3-1 loss at Mainz 05 on Saturday, a fourth consecutive defeat on the road in the Bundesliga this season which left them seventh in the standings.
Dortmund, who had a midweek confidence boost with a 1-0 home win over Sturm Graz, will now have to go back to the drawing board during the international break to attempt to turn their season around.
The defeat increased the pressure on coach Nuri Sahin, whose team are playing well in Europe but are not able to earn points away from home in the Bundesliga.
Dortmund, missing more than half a dozen key players through injury, struggled against Mainz and were left with 10 men in the 27th minute when captain Emre Can, under fire for his performances, launched a reckless studs-up challenge for a straight red card.
Things got even worse when Lee Jae-sung was left completely unmarked to head Mainz into a 36th-minute lead.
The South Korean then brought down Dortmund striker Serhou Guirassy in the box for a penalty five minutes later which the Guinea international converted.
The Dortmund defence, however, 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 from close range, his first ever league goal.
Dortmund, who have lost four of their five away games this season and drawn the other, could not find a way back into the game and the hosts missed several chances to add to their tally.
The Ruhr valley club is on 16 points in seventh spot with Mainz three points behind in ninth.
(Reporting by Karolos Grohmann, editing by Ed Osmond)