An early brace from Pierre-Emerick Aubameyang set up Dortmund's comprehensive 4-0 win over Galatasaray in Istanbul on Wednesday, leaving the Turkish club bottom of Group D in the UEFA Champions League with just one point and minus seven goal difference.
But while Galatasaray's coach Prandelli was disappointed with the defeat, he maintained his main goal of the 2014-15 season is to help the club win their 20th Turkish Super Lig title - effectively conceding his team are not at the same level as Group D rivals Dortmund and Arsenal.
Galatasaray sit second in the Super Lig standings, one point behind Besiktas after six rounds.
"We shouldn't be demoralised," the Italian said.
"Our aim is to win the 20th title in the history of the club. We'll be working for this.
"We're up against big teams in the UEFA Champions League. The club we played today was one of the teams feeding world champions Germany. We should continue working without ever giving up."
Captain Inan agreed, although he added that losing in any competition would not help them achieve their goals.
"We are trying to implement a system to fit our players, to fit our team, and sometimes it fails as we saw tonight," he said.
"Of course we will get over that. As I said, it is not easy to play in the Champions League.
"Our main target is the domestic title this year but such defeats will have a negative effect on confidence."
Inan insists, however, that Galatasaray could still advance to the knockout stages of the Champions League despite losing to Arsenal and Dortmund in successive matchdays.
"Two years ago we had one point after three matchdays but went on to finish in second spot and eventually reach the quarter-finals. We can repeat that," the 29-year-old midfielder said.
"If there is the slightest hope, we will pursue it. But as I said, we need to learn from the mistakes we made. We should not repeat them over and over again."
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