Borussia Dortmund defender Mats Hummels has admitted that the German champions face a tough task to reach the last 16 of the Champions League.
BVB need to beat Marseille by four goals in Tuesday's home game and hope that Arsenal defeat Olympiakos in order to qualify from Group F, and Hummels feels it will be close to impossible to make it to the next round.
"We know it's nearly impossible because Arsenal need to win in Piraeus and they've made it through to the next round – so I don't think they'll play their best team. I've told Per Mertesacker I'll kick him if they don't win there," Hummels said to uefa.com.
"If we'd won and Marseille had won as well on matchday 4, it would still have been the same for us. We need to score four goals against Marseille at home; it's really difficult.
"We need to have a really good game against Marseille, and a little help from Arsenal."
Dortmund were beaten 3-0 by Didier Deschamps' men away from home in the reverse fixture.