Spurs ran into an in-form Lionel Messi at Wembley on Wednesday as Barca beat Pochettino's side 4-2 to leave Tottenham without a point after two games in Champions League Group B.
The manager is mindful his side will be expected to beat Cardiff on Saturday and is keen to avoid complacency against a team that has claimed just two points from seven league games.
"I think with full respect to Cardiff, it will be a tough game too," he said at a news conference.
"In the Premier League there are no easy games. Everyone can think the motivation [is] to play against Barcelona and it looks like now we are going to play Saturday and it will be an easy game. For me, it's the opposite.
"The most difficult game is the game that everyone believes outside of the team that you must win. For us, it's so important to be motivated in the same level; if not, we are going to struggle.
"There are a lot of examples in football when you don't respect the opponent.
"But we have full respect to Cardiff. It will be so tough. It has been difficult to beat them for different teams. We were watching.
"I think [they have] a similar style or philosophy to Huddersfield [Town] and it was so tough for us to beat them. Of course, they are three important points that we have ahead.
"We're so focused in trying to not be affected by Wednesday. It's true the effort was massive, but we need to be ready. The competition doesn't wait for you. We need to be ready again to play."