Real Madrid are in for a tough test after being drawn against Galatasaray in the quarter-finals of the Champions League, director Emilio Butragueno has said.
Jose Mourinho's side reached the last eight when they came from a goal down to beat Manchester United at Old Trafford.
But Butragueno said they would have their work cut out once more when they take on a team including Didier Drogba and Wesley Sneijder.
"We are in the quarter-finals of a major European competition - that is never easy," he said.
"They did great work against Schalke [winning 4-3 on aggregate]. It was not an easy situation for them, but they knew how to overcome it."
He said the additions of Sneijder and Drogba had made the Turkish club "even stronger" and warned that Real would need to be on their mettle away from home in the second leg.
"We know how passionate their fans are," he added. "We will need to get a good result at home to take with us to Turkey."
Madrid assistant boss Aitor Karanka cautioned fans against believing Galatasaray would be easy to beat.
"If they are in the quarters, it must mean something," he said. "They have players with a lot of experience, important players like Drogba.
"But we still have La Liga games to play - there will be time to study our opponent and talk about them."