The Villans host the second-leg of their Champions League round 16 tie holding a 3-1 aggregate lead.
“He (Unai) has been really consistent with his message,” said Cash.
“And I think us, as players, know every team in the Champions League can be really hurtful.
“Obviously, we have the two-goal lead at the minute, but there’s been many occasions in the past where teams have been leading the first leg and then crashed out after the second.
“We have to be consistent and ready for the challenge.”
Cash added: “Our full mindset is to win the game and to do everything we can to qualify.
“I know we’ve got the two-goal lead but, for us, it’s a 0-0 game and we’re starting again.
“We want to try and win the game and it would be good if we could.”
On Club Brugge, the fullback also said: “I did an interview after the game at Brugge and they’re a good team. Obviously, we played them a few months before and they showed how dominant they were.
“I think we had a great result there, we put in a good performance, a strong performance.
“But I think there were chances in the game at 1-1, it could have gone either way, really.
“I won the penalty and made it 3-1, which is good to get another goal, 2-1 is always a little bit risky but to go 3-1 up is really good away.
“But they’re a fantastic team, they beat Atalanta in the round before and Atalanta are really good.
“So, it shows how consistent and dominant they are.”