France star Zinedine Zidane has warned his current club Real Madrid to take nothing for granted when they face Germany's Schalke 04 in the last-16 of the Champions League.
Title-holders Real could be forgiven for expecting little opposition in Gelsenkirchen for the first-leg on February 18 with the return in Madrid on March 10.
Carlo Ancelotti's Real inflicted a record 6-1 defeat on Schalke at exactly the same stage of the competition last season.
Madrid ran riot at the Veltins Arena as Karim Benzema, Gareth Bale and Cristiano Ronaldo each scored two goals as Schalke were hammered before also losing 3-1 away for a 9-2 aggregate defeat.
But Zidane, who currently coaches Real's reserves, says the first-team should take nothing for granted this time in Gelsenkirchen.
"I would like to say that Schalke has no chance and Real will safely reach the quarter-finals," the 42-year-old ex-Real midfielder told German daily Die Welt on Sunday.
"But in the knockout phase anything can happen. In two games, you have double the chance of an outsider playing above themselves.
"You must always be cautious -- especially against a German team."
Real have won only three of their 27 away matches in Germany.
Two of those victories came last season when they smashed Schalke, then routed Bayern Munich in the semi-finals on the way to winning the title.
Current Schalke boss Roberto di Matteo won the 2012 Champions League title with Chelsea and has helped the Royal Blues climb to third in the Bundesliga since taking charge in October.
Despite preaching caution, Zidane believes Real will progress to face Pep Guardiola's Bayern Munich in the Champions League final at Berlin's Olympic Stadium on June 6.
It was there that he infamously headbutted Italy's Marco Materazzi to earn a red card as France lost the 2006 World Cup final in his final match before retiring.
"(Bayern-Real) would be the logical final, but logic has no place in football," said Zidane.
"Past a certain level, there are no small teams anymore, especially not in the Champions League.
"There are no easy victories, those days are long gone."
Real destroyed Bayern 4-0 in the second-leg of last season's semi-finals to take the tie 5-0 on aggregate, but Zidane says Guardiola has given the Bavarian giants "that little extra."
"He has put them amongst the best in the world and given them an extra little kick," said Zidane, after Guardiola's first 18 months in Munich.
"He brings his own unique touch to Munich's game and that makes the difference."