When Liverpool boss Jurgen Klopp sanctioned the sale of Philippe Coutinho to Barcelona in January, many Reds fans feared the worst.

At the time he went to Spain, Coutinho had made more Premier League chances and assists than any other Liverpool player and, in open play or from set-pieces, did more than anyone else to make the team tick.

Allowing their playmaker to leave midway through the season not only threatened to derail Liverpool's promising campaign, but by taking the cash they arguably signalled a distinct lack of ambition too.

But three months on, as a free-scoring Reds side prepare to take on Roma in the first leg of their Champions League semi-final on Tuesday (19:45 BST kick-off), it does not seem like they are missing the £142m man very much after all.

Jurgen Klopp did not appreciate the 'Fab Four' nickname given to Sadio Mane, Coutinho, Roberto Firmino and Mohamed Salah because he felt it did not reflect the achievements of the entire team but, between 4 November and Coutinho's final appearance for the club on 30 December, the quartet scored 34 of their side's 41 goals in a prolific 13-game spell

"You cannot say they are better without him, because we do not know where they would be in the Premier League if he had stayed - but they have definitely adapted," says former Liverpool full-back Stephen Warnock.

"There is more emphasis on the front three to create more for themselves now, because they haven't got Coutinho behind them to create for them.

"And there is a better balance to the team too. Everyone is talking about the difference [£75m defender] Virgil van Dijk has made - and he has been immense at the back - but having another midfielder who is more defensive-minded than Coutinho has definitely helped as well.

"Liverpool have been improving as the season has gone on anyway, and there are several reasons for that, but it will have taken people by surprise that they have kicked on the way they have since selling Coutinho.

"They obviously believed they could deal with him leaving - and they have."

Liverpool's most creative player: When he left the club on 6 January, Coutinho had made 40 Premier League chances for Liverpool in 2017-18 - Salah had made 35, Firmino 33 and Mane 23. He had also made six assists this season - Salah had five and Mane and Firmino had managed four each.

What's changed? A collective effort in midfield and attack

Since Coutinho's exit broke up the so-called 'Fab Four', Liverpool's attack is looking more lethal than ever. But why?

Between them, Sadio Mane, Roberto Firmino and Mohamed Salah have created 71 chances for each other this season, more than Coutinho, Firmino and Mane managed in the whole of 2016-17, and more of those chances are resulting in goals too.

Mane, Salah and Firmino have created 71 chances for each other in the Premier League and 17 of those have ended up being scored. Last season, the trio of Coutinho, Firmino and Mane created fewer chances all season (66) and only 10 ended in goals.

"It has not just been Salah on his own individually, they have done it collectively," Warnock explained.

"That is probably the biggest delight for Klopp, because he has got all three of them making goals for each other as well as scoring them.

"I love the way Salah can make something happen out of nothing in the same way [Barcelona forward] Lionel Messi does, and his brilliance has actually freed Mane and Firmino up more too.

"People are so petrified of Salah that they cannot worry about the other two, and it means they are causing damage when he's not. If I was lining up against them, I wouldn't know what to do.

"Then you have got the three behind, who understand they have got to do more for the strikers now Coutinho has gone.

"Previously, the midfield would win it and they would look for him straightaway to be the one to create, whereas now they are becoming the creators because they have to."

Danny Ings' goal against West Brom on Saturday was the first in the league for Liverpool since 30 January not to involve any of Salah, Mane or Firmino as either the scorer or the player providing the assist

Unpredictable in attack? 'They break like the Red Arrows'

Klopp feels that shared responsibility when Liverpool move forward means they are more unpredictable than they were with Coutinho in the side.

Warnock also thinks it means they are more likely to play to their strengths - ripping teams apart with the speed of their attacks, with several players able to provide the finish.

"They just break like the Red Arrows," the Englishman added. "When they run, they all burst forward and it could be any one of them who scores - whoever gets in the right position.

Liverpool's starting line-up in their 3-0 Champions League win over Manchester City was typical of Klopp's team's in the second half of the season in that it featured three industrious midfielders who also contributed to their attack - James Milner teed up Alex Oxlade-Chamberlain for their second goal on the night

"I think that has been a big positive too. They are not selfish when they get there because they understand that everyone is making a run for a reason, and they just try to pick the right pass.

"When Coutinho was in midfield, he tended to hold on to the ball quite a bit and be a dribbler. Because he had the ability to hold on to the ball and protect it, he maybe slowed the game down a little bit.

"Now, that midfield three tend to move it quite quickly and simply, and get it to the front three as quick as they can."

Fewer shots from distance? You find a different way to win games

One of Coutinho's trademarks in a red shirt was his spectacular shooting from distance, and for good reason. During his time at the club, he scored more Premier League goals from outside the box than any other player.

But for every effort he brilliantly bent into the top corner, there were many more that were blocked or ended up in the stand.

In Liverpool's 2-0 defeat at Burnley in August 2016, for example, Coutinho had 10 strikes from outside the box, but only one forced the goalkeeper into a save.

Liverpool's 2-0 defeat at Burnley in August 2016 was an example of when they looked to Philippe Coutinho for inspiration to break down a team - but he was below his best. Nine of his 10 shots (left-hand graphic) were either off target (red arrows) or blocked (yellow). His passing (right-hand graphic) was also uncharacteristically poor - although he made more passes than any other Reds player in the Clarets' half, his display was littered with misplaced passes (red arrows) and his only key passes (yellow arrows) were sideways or backwards rather than into the box.

Since he left, Liverpool have taken fewer shots overall, but also fewer from outside the box - an average of six per game compared to 7.1.

However, their shot conversion rate (excluding blocks) has gone up - from 17.4% to 21.6% - which suggests they are creating better chances as well as having players in form to finish them.

"If you haven't got that type of player in your team any more, then you have to realise that is not a way you are going to win games," added Warnock.

"You have to look at other ways - which is why you now see Liverpool working the ball into the box far more than they did before."

Coutinho, shown here bending home a shot from long range against Hull in September 2016, scored 19 Premier League goals from outside the box between his Liverpool debut in 2013 and his final league appearance - four more than any other player. Overall in his Premier League career, he attempted 90 shots on target from outside the box - meaning 25% of Liverpool shots on target from outside the box during his career at the club came from him.

There is a difference defensively too

Van Dijk's arrival from Southampton has undoubtedly made Liverpool look more secure at the back, but has Coutinho's exit played a part too?

"When Coutinho was playing in a deeper midfield position, you are almost losing a man defensively," said Warnock.

"Yes, he closed down - but he does not close down like the current midfield trio do. That is a big reason Liverpool have been doing so well.

"It starts from the front, of course. I was at Etihad Stadium to watch Liverpool beat Manchester City in the Champions League and at times only their three forwards were pressing six City players around their area.

"The Liverpool trio of Mane, Firmino and Salah were outnumbered but they were very clever with the way they did it - with their body shape as they closed City players down and their speed and acceleration.

"They actually decelerated at the right time too, and it was brilliant to watch. It must be a nightmare for defenders, who have got those three running at them one way but also hassling them when they are on the ball.

"Liverpool's forwards are just as quick to close you down as they are when they are attacking, which is frightening really.

"Behind them, they know they have got three more players doing exactly the same if the ball does get through."

Manchester City's defeat at Anfield earlier this month was the first time they did not manage a shot on target in a game since October 2016. They had seven shots off target (red arrows in left-hand graphic) and four efforts blocked (yellow circles). Pep Guardiola's side made 21 crosses but 19 of them were unsuccessful (red arrows in the right-hand graphic).

'A trust in the team and a belief in what they do'

Trent Alexander-Arnold was seen as a potential weak link in Liverpool's Champions League tie against Manchester City but he rose to the occasion and put in a brilliant performance to stifle Leroy Sane. In the first leg at Anfield, the Reds right-back made more clearances (10) and interceptions (seven) than any other Liverpool player, and won possession the most times (10) too

If Liverpool are working together to get results, they are also sticking together when things do go wrong.

"One of the things I really like when I watch Liverpool is you never see them arguing with themselves on the pitch," Warnock added.

"You never see them getting disappointed with each other if someone did not press correctly or do what they were supposed to.

"Instead the reaction seems to be more along the lines of: 'Well it did not work this time but we know you will be in there next time.'

"It is the same with Klopp and his players. Some managers would have taken Trent Alexander-Arnold out of the team after he had tough days against United and Palace - but Klopp stuck with him against City and he had a brilliant game.

"There is trust in that team and a belief in what they do. That comes from results, but they know they are getting those results because they are doing the right things."

Reds reaping rewards of Klopp's learning curve

Premier League Show: Jurgen Klopp interview

Behind all this improvement is one man.

Warnock feels Klopp has learned a lot in his two and a half years in the Premier League, which is why the Reds are reaping the rewards.

"You can see that he has worked out what went wrong last season, and he knows when players can and cannot be rested," he said.

"Hearing from people who play for the team now, he has changed his training schedule to suit the intensity of the Premier League.

"Liverpool play a massively fitness-based game and I am not surprised it has taken some players time to adjust to that.

"When they faded in January last season, the theory was that they were tired and running out of steam. Not any more. If anything they are getting stronger.

"Look at what happened after they lost to Manchester United at the start of March. The great thing was they bounced back straight away."

Trust Klopp - with tactics, training and in the transfer market

Any team in the world would miss Coutinho - Klopp

Despite Liverpool's progress, there have been some who have doubted Klopp's vision for the club - especially when he decided Coutinho could go.

"I know fans were worried it was the wrong move but that kind of money means it is good business," added Warnock.

"And I don't think there are many players Klopp has bought or sold in his time at the club you would say was a terrible buy, or who we are missing.

"In fact, I would hold my hands up and say his transfer business has been incredible. He has not turned his squad over or brought in a massive influx of players. And his approach is good for the dressing room.

"That is another reason why the fans should trust him - he knows what he is doing whether it be tactics, on the training ground or in the transfer market."