Liverpool manager Jurgen Klopp has described Louis van Gaal as "one of the most successful coaches in the world" ahead of Sunday's clash against Manchester United at Anfield.
Klopp, who replaced Brendan Rodgers as Liverpool boss in October, has not yet experienced a showdown between the long-standing rivals.
After 21 games in the Premier League this season, the Merseyside outfit are ninth in the table, three points below sixth-placed United.
"Louis van Gaal is one of the most successful coaches in world football - he has his ideas on football and you have to respect this," Klopp told reporters in Friday's press conference. "We have to watch what we can find out and make a plan.
"You will not win against Man United because you ran 145 miles or something. You have to make the right decisions. Of course you can be over-motivated. That's possible. You don't need to think too much about motivation in these games, but you need the balance. That's what football is all about.
"If you don't do the right thing in the moment, you have to run more. Mistakes, you can only solve with your legs. You have to defend well because they have brilliant players. Two days to go, we can prepare. We are different characters. [Van Gaal] is more experienced. Maybe I'm more lively on touchline than him."
In September, United sealed a 3-1 victory over their arch rivals at Old Trafford.