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.