Assistant boss Andreas Hinkel insists RB Leipzig know Rangers are not in the Europa League last four simply to make up the numbers.
Of the remaining teams, the Ibrox side have been billed as underdogs with West Ham and Eintracht Frankfurt also vying for a place in the final.
Giovanni van Bronckhorst takes his players to Germany for a first leg showdown with Leipzig on Thursday having already knocked out Borussia Dortmund, Red Star Belgrade and Braga.
And former Celtic defender Hinkel, now right hand man to manager Domenico Tedesco, is wary of the "weapons" Rangers have at their disposal.
He said: "Scottish teams in general and the league, it's more physical compared to the German league.
"They have good mentality, it's not easy to play there.
"But it's not just physical, you know, they have their weapons.
"Especially Rangers, they are good in counter-attacks as well. Defending, strong defending.
"They didn't qualify for the semi-finals just to qualify, they beat some good competitors in this competition.
"So it's going to be really tough and hard to play against them."
Hinkel spent three years at Celtic Park between 2008 and 2011 but confessed he's not received much in the way of support from his old team-mates - owing to a change of phone number on the German's part.
He laughed: "Not that many messages because I changed my number!
"But I'm still in touch with some and I received a few messages."
