Aston Villa must handle a "difficult" atmosphere in their "biggest game of the season" as they look to come from behind against Olympiakos, says manager Unai Emery.
The Premier League side headed to Piraeus trailing 4-2 following the first leg of their Europa Conference League semi-final at Villa Park.
Emery admitted his side would have to be much improved to reach the final.
He said: "We must do better. It will be difficult with the atmosphere."
The former Sevilla and Arsenal boss added: "We need to build a new experience here with our players and our idea.