The Colombia international has stressed that the big teams encounter a lot of difficulties in European club football's second competition
The Colombia international previously won the competition during his time at Porto, and Guarin has insisted that it is not easy to go all the way in the Europa League.
"There are two types of difficulty in a competition like this: the first is that you're playing in far-flung places that are hard to get to and that means undertaking long journeys," Guarin stated at a press conference.
"The second is that you meet teams that are perhaps not so well known but who are tough to play against, fired up and determined to win."
The midfielder then went on to discuss Thursday's Europa League game versus Vaslui, and warned his team-mates not to underestimate their opponents.
"I think in this game it's a case of us playing against an opponent who everyone thinks will be pushovers. But we're going to have to be extremely careful because they are a team we don't know very well.
"They are going to be giving it their all and they'll be desperate to do well. We have to concentrate on winning, on playing well, on playing like Inter."
Thursday's first leg in Romania kicks off at 20:45CET.