Mendes left Rangers and joined Sporting Lisbon over the weekend, but the 30-year-old is confident his former team can cope without him.
“They will win the league. There is no doubt in my mind,” Mendes told the Daily Record.
“There is a long way to go but the way they are performing and their attitude, it is so good.”
Mendes also heaped praise on Rangers manager Walter Smith.
“I have worked under some top managers and Walter is right up there,” added Mendes. “It was a pleasure to work under him.
“He’s a great manager. Football wise and, as a man, he is a nice person and a real gentleman.
“I was delighted to have been given the chance to work under his command.”
