Real Madrid goalkeeper Diego Lopez says his side's Champions League quarter-final against Galatasaray remains open, despite the club taking a 3-0 advantage into Tuesday's second leg.
Lopez, 31, flew to Istanbul on Sunday with his Madrid team-mates, including fellow goalkeepers Iker Casillas, Antonio Adan and Jesus Fernandez. He is expected to keep his place in the starting line-up, even with club captain Casillas now fully fit after two months out with a broken finger.
The former Villarreal man told Madrid's official website that he believes Galatasaray will improve on their first-leg performance in front of their own fans at the Ali Sami Yen stadium.
"The tie is not over because we know what football is like," Lopez said. "We are going to a difficult stadium to face a team which did not show their best in the first leg. They are better than they showed. We will have to remain alert."
An away goal on Tuesday, though, would likely seal Madrid's progress to the semi-finals, Lopez admitted.
"It is clear that 3-0 is a very good result for us, but I believe the key will be to score a goal there," he said. "Then the tie will be practically over. It is rare that we do not score in a game. A goal would leave us in a great position because they would have to score five against us, and it would be an uphill struggle for them."
Madrid warmed up for the game with a 5-1 stroll past Levante in La Liga at the Estadio Santiago Bernabeu on Sunday.
Champions League top scorer Cristiano Ronaldo, with nine goals in nine games, also scored against Levante, despite only playing the final 45 minutes.
Former Madrid youth teamer Lopez, on the wrong end of a Ronaldo hat-trick when at Villarreal in January 2011, said he preferred having the Portuguese as a team-mate rather than an opponent.
"I suffered a lot as his rival during my time at Villarreal, and now I enjoy training and playing matches with him every day," he said. "He is a player who can make all the difference, who is always there at key moments, which is when great players like him have to make their mark. We can see that in all the crucial matches he scores goals, he is there, and that is very important for the team."
Lopez also gave his predictions for this week's other Champions League quarter-finals.
"[Barcelona against Paris Saint-Germain] will be a tough match for the two sides," he said. "Barcelona come into the game with a slight advantage, but I believe it is one of the closest ties. Bayern got a very good result, but Juve is a great team. At 2-0 it leans towards Bayern, but Juve are having a great season. I hope Malaga make the semi-finals as they are a Spanish team, but it is going to be hard for them. Dortmund showed against us [Madrid] in the group stage that they are a great team."