It’s all about Mohamed Salah.
If the newly crowned PFA Player of the Year continues his scoring streak, Liverpool will have one foot in the Champions League final.
If Roma can keep the Egyptian goal machine under wraps over two legs, starting at Anfield on Tuesday night, they will have gone a long way towards their own first appearance in European club football’s showpiece in 34 years.
And, of course, the Italian side have a better idea than most about stopping Salah, having him on their books for two seasons, the first on loan from Chelsea, before his £38m move to Liverpool before the start of the current campaign.
Since then the 25-year-old has been in rampant form, scoring in 32 of the 46 matches he has played.
So far he has 41 goals to his name and remains on course to break the 38-game Premier League record of 31 he now jointly holds with Alan Shearer, Luis Suarez and Cristiano Ronaldo.
He may even smash through the mark of 34 set by Shearer and Andy Cole over a 42-game season and he has his sights on Ian Rush’s Liverpool record of 47 goals in a single campaign.
Reds boss Jurgen Klopp knows the value of his star player to his side and he’s sure that his former team mates will take an uncompromising approach to the man known around Anfield as the Egyptian King.
"Players change clubs, managers change clubs - I had it with Dortmund two years ago already," said Klopp.
"It is a normal game but it feels quite special because you know much more about the team than you usually know, and you are more interested in the other team than you usually are.
"I am pretty sure Mo follows the whole season of Roma as he had a fantastic time there and he became the player there which we have now here, so big credit to all the staff and the players at Roma because they are all part of his development.
"Italian defenders are famous for not having friendly games so I think Mo will feel pretty early in the game they are not his team-mates any more and then he can strike back in a football way."
This season's 41-goal tally has already eclipsed the 34 in 83 appearances he made in two seasons at Roma.
He averages a goal every 92 minutes in the Champions League and has a better conversion rate than the competition's top scorer Cristiano Ronaldo of Real Madrid.
He is the archetypal Klopp player and the manager has built a high-tempo game plan around the pace of Salah, Sadio Mane and Roberto Firmino. Between them they scored four of the five goals that put them through over two legs against Premier League champions Manchester City in the last round.
If Liverpool weren’t expected to be at this stage of the completion at the start of the season, and they really weren’t, Roma are the genuine surprise packages.
This is their first semi-final in the Champions League/European Cup since 1984, when they went on to lose the final to Liverpool on penalties at their Stadio Olympico home in Rome.
They’re third in the Seria A table, 18 points behind leaders Juventus and have no great European pedigree to speak of.
But they have put in consistently solid performances in the Champions League this season, reaching a high-point with their stunning 3-0 home win over Barcelona in the quarter-final to go through to the last four on away goals.
Veteran Daniele De Rossi was a World Cup winner with Italy in 2006 and forms a solid midfield base with Belgium international Radja Nainggolan and Dutchman Kevin Strootman.
Edin Dzeko, Aleksandar Kolarov (both Manchester City) and Federico Fazio (Tottenham Hotspur) are all known from spells in English football, while their Brazilian goalkeeper Alisson is highly rated and has long been linked with a move to Liverpool.
In five Champions League games in Rome this season, against Atletico Madrid, Chelsea, Qarabag, Shakhtar Donetsk and Barcelona, Roma have not conceded a single goal.
In each of the previous two knockout rounds they have advanced on away goals having lost the first leg on their travels, and that should be a warning to the Liverpool side that journeys to Italy for the second game.
Roma have been managed by Eusebio Di Francesco since June and following a career in the dugout at the less glamorous end of the table he has enhanced his reputation with the club he enjoyed four years at as a player.
Older Reds fans will have happy memories of the Stadio Olympico though, having seen their team win the European Cup there in ’84 and in 1977 against Boruissia Monchengladbach.
While Roma enjoyed a 3-0 win over relegation battlers SPAL on the domestic front at the weekend, Liverpool threw away a two goal lead to draw 2-2 to Premier League bottom side West Bromwhich Albion.
Their home form though, and with the at-times deafening the backing of their fans, has been exceptional.
In European terms, they have lost only one, against Real Madrid in October 2014, of the last 20 European matches at home and are unbeaten at home in the last 15, winning 10 and drawing five.
Klopp is likely to make changes from the West Brom draw, with Alberto Moreno, Ragnar Klavan and Joe Gomez all making way in defence for Andrew Robertson, Dejan Lovern and Trent Alexander-Arnold.
Danny Ings will be stood down in attack with Firmino returning and a possible midfield change could see Alex Oxlade-Chamberlain replace Gini Wijnaldum.
Back at Melwood with Mo! 🔴👑🏆 pic.twitter.com/2ipjK696zz— Liverpool FC (@LFC) April 23, 2018
Before the quarter-final first leg against Manchester City, which ended in a stunning 3-0 win, Liverpool supporters outside Anfield attacked the City bus.
This has led Merseyside Police to vow a crackdown on any fan disturbances around Tuesday’s game.
"Our policing style will be firm, fair and friendly, but we will take action where necessary against those individuals who may seek to cause problems or misbehave and spoil the evening for the majority of supporters," said chief superintendent Dave Charnock.
These will be the sixth and seventh meetings between the clubs in Europe, Liverpool having won three, lost one and drawn one of those.
They came out on top in the ’84 final, and progressed in the Champions League in 2002 after a 2-0 win at Anfield and a scoreless draw in Rome. Roma’s sole win to date came in a 2001 UEFA Cup tie, but they lost 2-1 on aggregate as Liverpool went on to win the competition later that season.