Borussia Dortmund coach Thomas Tuchel has warned his players not to take too many risks in the first leg of their Europa League round-of-32 tie with Porto.
The Bundesliga side will be looking to take a big step toward the next round when they host Porto on Thursday, but Tuchel has stressed that trying to settle the tie in the first leg could come at a cost.
"Porto are a team that is very compact and well organised. They will be keen to be at their best in Europe," the Dortmund coach said at a news conference.
"We need two great performances to reach the next round. It does not mean anything that we have the home advantage in the first leg. We cannot afford to make the mistake of trying to force something. We have 180 minutes to decide the tie.
"I am looking forward to this strong opponent and expect two intense games.
"[Pierre-Emerick] Aubameyang will play if nothing happens before Thursday. He has been training without pain.
"[Roman] Weidenfeller, [Nuri] Sahin and [Ilkay] Gundogan have been training seperately because of a virus. They are doubtful for Thursday's game."