Liverpool boss Jurgen Klopp says Manchester United counterpart Jose Mourinho has never lacked ambition, describing him as the "most successful manager" in the world.
The pair go head to head at Anfield on Sunday, live on Sky Sports, with United attempting to end Liverpool's unbeaten start to the season.
Mourinho has used defensive tactics on his last two visits to Anfield, which have both ended in goalless draws, but Klopp says United were not lacking ambition.
"I don't think that Jose Mourinho ever has a lack of ambition, ever," said Klopp in his pre-match media conference.
"He just makes what he thinks is right in the moment - that makes him the most successful manager in the world."
Despite United being 16 points behind league leaders Liverpool, Klopp does not believe their position will have any bearing on Sunday's fixture.
"There is a lot of quality, a lot of quality. There is speed, technique, they are physically strong - they have pretty much everything," added Klopp.
"They still have [David] De Gea in goal, who is unbelievable. They have strikers, they can switch between [Marcus] Rashford, [Romelu] Lukaku, they have [Jesse] Lingard and [Anthony] Martial.
"They have unbelievable quality, so we don't judge them by the points they have, we judge them by the quality they have and we'll prepare for that."