The Westphalians host Real Madrid in the first leg of their Champions League semi-final on Wednesday and, while that fixture is going to be in the back of their minds, Klopp insists they will not be neglecting their Bundesliga obligations.
"Of course it's paramount that nobody gets injured, but we are focusing fully on Mainz and will field a team who we think can beat them," he said.
"Mainz have a very bad home game behind them (against Hamburg) and, since I know them, they will have been working hard this week trying to find the tactical solutions for it, and they will want to use us as a test.
"It is going to be intense so if we take away just one per cent with Real Madrid in mind, then that would be too much, which is why we are concentrating on Mainz."
Klopp knows Mainz will be up for the trip to the Westfalenstadion.
"We have the best stadium you could imagine and it is practically always full, so our opponents tend to make this into a highlight, and that makes it uncomfortable," added Klopp.
"They are a side who have shown that they can raise their game against the big sides. I think their record against Bayern Munich since Thomas Tuchel took charge proves that."
For all his talk of prioritising the Mainz game, Klopp is still expected to make changes to his starting XI.
Marco Reus has not been training fully over the past few days, which is why he is a candidate for a break, while Sebastian Kehl has been ruled out of training until Monday.
Tuchel's injury concerns are arguably greater, but he promises he will "find 16 players" for the trip to Dortmund.
And those players should go into the game free from any pressure as the underdogs, according to Tuchel.
"Knowing you might lose is maybe not all that bad," he said. "That could unblock us and give us the relaxation we need."
Tuchel is hoping the likes of Marco Caligiuri, Elkin Soto and Andreas Ivanschitz will recover to allow him to name the full complement of seven substitutes on the bench.