Raul has warned Real Madrid to take nothing for granted in their Champions League last-16 clash with Schalke, claiming that the Germans will "fight right to the end".
The legendary Spanish striker, who spent two seasons in Gelsenkirchen after a 16-year spell at the Santiago Bernabeu, feels that the Liga outfit are the clear favourites to progress to the last 16.
However, he feels that it would be very foolish for Carlo Ancelotti and his men to underestimate the threat posed by Schalke, whom they will face at the Veltins-Arena in Februaryh.
"It's going to be a special play-off for me," Raul told Madrid's official website. "It's going to be great for Schalke and I'm really happy that my [former] team-mates and the fans are going to experience this play-off.
"Real Madrid are better than Schalke but you always have to be careful with German teams because they fight right to the end.
"[Schalke] have a very good team as well."
The 36-year-old, who is Madrid's all-time top scorer, is currently plying his trade in Qatar with Al Sadd.