The Spain boss says the Turkish giants are evenly-matched with their Champions League opponents, and has heaped praise on January signings Didier Drogba and Wesley Sneijder
The Gelsenkirchen club have been in poor form of late, while the Super Lig side have been boosted by the January arrivals of Didier Drogba and Wesley Sneijder.
"[They are] two teams who play good football, and they'll be two difficult matches," the former Spain international told Turkish media outlet Bugun TV.
"They're equal, for me. Galatasaray have the same chance as Schalke. But Galatasaray are motivated for such competitions and do well.
"They [Drogba and Sneijder] are very good transfers. Chelsea's Champions League win last year depended very much on Drogba's performances, I think.
"He's a very brave, very good player. Sneijder is also a top-quality midfielder."
The former Real Madrid boss also spoke about his relationship with Besiktas, who he coached during the 2004-2005 season.
"I have never said a word against the Besiktas board, no matter what happened," Del Bosque added. "I do not have any grudge against them.
"We were happy in Istanbul, and we need to accept that things happen in football. We tried to do our best. We have fantastic memories from there. I always want Besiktas to do well."