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).

Edin Terzic warned Borussia Dortmund must swiftly forget about their Champions League heroics in Paris after a 3-0 humbling by Mainz on Saturday.

Lee Jae-Sung twice punished a sloppy Dortmund performance after Leandro Barreiro had opened the scoring for relegation-battling Mainz in their Bundesliga clash.

That abject performance came after BVB managed a 1-0 away victory against Paris Saint-Germain, progressing to the Champions League final after a 2-0 aggregate victory over Luis Enrique's side.

Dortmund head coach Terzic was far from impressed after defeat against Mainz left his side four points adrift of fourth-placed RB Leipzig in the German top flight.

"Let's let Paris be Paris and talk about last week and this week," Terzic told Sky Sport Germany.

"The starting position was similar to last week. Except now we were always late and outnumbered.

"It was a deserved defeat, especially because of the first half."

Marco Reus echoed Terzic's sentiment after Dortmund came crashing back down to earth following their European success.

"If you see the first half, it's deserved, even at the highest level," the Dortmund veteran added.

"We expect more from ourselves. There was still a lot at stake for Mainz.

"It was important for us to continue to gain self-confidence. That just was not good today. This is a pity."

Dortmund will hope to respond when they host Darmstadt next Saturday before their Champions League final against Real Madrid on June 1 at Wembley Stadium.