Liverpool manager Jurgen Klopp responded to his side’s FA Cup defeat by Manchester United by saying “don’t worry about us”.
The loss to their fierce rivals means Liverpool have now won only one of their past seven games.
The defending champions have also fallen to fourth in the Premier League, six points behind leaders United.
“I saw a lot of steps in the right direction and that’s all good,” said Klopp.
Liverpool won the Champions League in 2019 and stormed to the Premier League title in 2020, finishing 18 points ahead of second-placed Manchester City and 33 in front of United in third.
However, they have gone five games without a win in the league and their only win in the past seven was in the FA Cup against a youthful Aston Villa, whose senior team had been hit by coronavirus.
Liverpool took the lead through Mohammed Salah at Old Trafford, their first goal after two blanks in the Premier League, only for Mason Greenwood and Marcus Rashford to put the hosts in front.
Salah drew Liverpool level before substitute Bruno Fernandes won it for United with a powerful free-kick.
“It’s not what we wanted, so it’s frustrating,” said Klopp. “We weren’t on our absolute top [level], but we made a lot of steps in the right direction.
“You don’t have to worry about us, as a group we are really together.”
‘We’re gradually getting better’
United have now lost only once in 13 games - a 2-0 defeat by Manchester City in the semi-finals of the EFL Cup - since going out of the Champions League at the beginning of December.
“We’ve found a way we believe in, the players believe in and we’re getting stronger and stronger,” said manager Ole Gunnar Solksjaer.
“It’s fantastic to win games against last year’s champions - they’re a fantastic team.
“We’re gradually, layer by layer, getting better, winning tight games, so the morale and confidence is very good.”
United did suffer a concern over the fitness of Rashford, who will have a scan on Monday after being substituted with a knee problem.
“Let’s hope so,” said Solskjaer, when asked if Rashford was suffering from a minor issue. “His knee was bothering him, so a scan tomorrow and we’ll see where we are.”
‘Fernandes the difference’
Just under a year after his £47m move from Sporting Lisbon, Fernandes once again proved himself to be United’s talisman, coming off the bench to drill in the winner.
Since he made his debut for United last February, no other player at a Premier League club has scored more than Fernandes’ 28 goals.
“Bruno Fernandes has dragged Manchester United to the top of the league singlehandedly,” said former England midfielder Jermaine Jenas on BBC One.
Former England striker Ian Wright added: “Fernandes makes a difference because he is a top quality player.
“I am one of those who has doubted Solskjaer in the past but the way the squad has been is brilliant. It has been like an old Manchester United side. The way they have attacked the games, it’s a mentality of old.”
‘Hard to believe Fernandes impact’ - analysis
BBC Sport’s Simon Stone at Old Trafford
It is hard to believe the change in fortunes at Manchester United since Fernandes’ arrival from Sporting Lisbon.
From outsiders to finish in the top four, United are now top of the Premier League and capable of coming out on top in a thrilling meeting with a Liverpool side that left the pack trailing in their wake as they ended that 30-year wait for a league title last year.
If someone was going to win this game with a precise free-kick into the corner from the very edge of the area, it had to be Fernandes.
Yet there is so much to admire about United at present. Paul Pogba, who started in central midfield and finished on the right, has got his mojo back and suddenly looks to be the world class player he is frequently spoken of as, not the player who so often fails to live up to that billing in club colours.
Dean Henderson is settling into Old Trafford life and produced some important saves as Liverpool rallied. Luke Shaw is a man reborn, reaching a level of consistency both in attack and defence not seen since his Southampton days.
Marcus Rashford’s all-round game is improving massively. Through his own ability and the demands he makes of others, veteran striker Edinson Cavani is starting to have a significant impact on how United perform.
There are weaknesses about Ole Gunnar Solskjaer’s squad. But as Pep Guardiola wrestles with how to cope without Kevin de Bruyne and Brendan Rodgers is doing the same with Jamie Vardy, suddenly, United look like the team to beat, which no-one has said for a long time.
That is not to discount Liverpool. In a game of tiny margins, they could have come out on top. Had they done so, Jurgen Klopp’s ‘problems’ might not look quite so large. Klopp has too many players who have been too good for too long for a comeback not to happen.
But for now, United are in a good place - and, with Fernandes around, they are well-placed to stay there.
Solksjaer’s credentials have been questioned repeatedly but today’s win, his first against Liverpool, means he has now beaten every other big six team at least once since replacing Jose Mourinho as boss two years ago.