Jurgen Klopp has warned Manchester United are nothing like the side Liverpool met earlier this campaign, pointing at Henrikh Mkhitaryan's resurgence to illustrate how they have changed.
Liverpool had to settle for a scoreless draw from a drab meeting at Anfield back in October, with Jose Mourinho's men struggling to find their best form in the opening stages of 2016-17.
United have significantly improved since, though, and are on a nine-game winning run in all competitions, with Mkhitaryan, Zlatan Ibrahimovic and Paul Pogba leading the way.
United's superb run of form has seen them close to within five points of second-placed Liverpool in the Premier League table and Klopp realises a tough task awaits at Old Trafford on Sunday, with the German's side criticised for a limp display in a 1-0 defeat to Southampton in the EFL Cup semi-final first leg on Wednesday.
"United are better and more confident than when we faced them in October. They are more used to each other. Mkhitaryan is an example, now they can use his quality. It is a different side," Klopp stated at Friday's news conference, singling out his former Borussia Dortmund attacker for praise.
"Mkhitaryan combines skills at the highest tempo. Good finisher, good attitude, good worker. Can play different positions and he is a world-class player, no doubt.
"We will go to Manchester and line up so we are ready for the challenges in the game. When I woke up I thought 'oh yes, only two days to go'. I know some say 'oh my God' because of the loss to Southampton but we will be competitive.
"Our passing needs to be quicker and earlier. It was only one game where we did not create a lot of chances.
"The upcoming games against United and Chelsea are important. We cannot ignore it. But the season does not end after it. These games are important in the season. It would be nice to win there but we have a lot of games to play. There are lot of points to get after this.
"It is a real challenge. We go out there for a result, no other reason. Last year, I managed for the first time at Old Trafford. It was intense with a great atmosphere. I do not have to let the players know about the history of this game. They are responsible. The players know more about it than me. It is not about making it bigger. It is very big but it is just football. There is no time to be looking for excuses, you have to be ready.
"Of course, we are excited about the opportunity to go there and play our best. Both teams are on a good run long term, and United have less injury problems. You can feel good before the game. We realise before the game that we are Liverpool and we need to show this. Everyone who wants to see a real fight for a game, then yes, watch it. It will be 100 per cent from our side."