London - Roma know the threat posed by Mohamed Salah more than most having sold the free-scoring Egyptian to Liverpool for an initial €42 million just 10 months ago.
But that may not help the Italians much as they become the latest side to face the gauntlet of Anfield on a European night in Tuesday's Champions League semi-final, first leg as Salah has blossomed into a goalscoring machine very few saw coming at the start of the season.
Salah's then club record price tag was questioned at the time of the deal coming just two years after he failed to make an impression in the Premier League with Chelsea.
Now, though, it looks like an incredible bargain as Salah has netted 41 goals in 46 games to take Liverpool back to the last four of Europe's premier club competition for the first time in a decade.
"It wasn't like a lot of other teams than Liverpool were banging down the door," Roma's American co-owner James Pallotta told the BBC's World Football programme.
"I think today a lot of teams are kicking themselves in the head that they didn't take a closer look at him."
In a nomadic career since moving to Europe as a 19-year-old, Salah was known for his pace and dribbling ability in spells at Basel and Fiorentina either side of a short time at Chelsea before moving to Roma.
However, the capability he has shown time and again this season to keep a cool head in front of goal used to so often fail him.
Most famously of all, Salah missed a series of one-on-ones with Real Madrid goalkeeper Keylor Navas as Roma bowed of the Champions League at the last 16 to the side that would go onto win the competition in 2016.
"In Roma he was amazing. Every game he created a lot of chances, but sometimes missed," said Manchester City manager Pep Guardiola, who suffered from Salah's new found confidence in front of goal as he scored in each leg of Liverpool's 5-1 aggregate thrashing of the Premier League champions in the quarter-finals.
"This season I think the way Jurgen Klopp wants to play is perfect for him. I think Jurgen is a master to buy players with what he really needs for the way he wants to play."
Pallotta agrees that Klopp's system of a fluid front three also including Roberto Firmino and Sadio Mane is what has brought the best out of Salah, who had to feed off the target man figure of Edin Dzeko at Roma.
"He's obviously had an incredible year. I think the coach there has clearly figured out how best to utilise him, using him in a different position I would say to Roma because you've got Dzeko in the middle."
Despite Liverpool's heroics against City in the last eight, they were upstaged by Roma for performance of the round.
The Serie A side overturned a 4-1 first leg deficit to beat Barcelona on away goals by shutting out Lionel Messi and a former Liverpool favourite Luis Suarez in a famous 3-0 second leg win.
However, a record of losing their last three Champions League games on the road - conceding eight goals in the process - doesn't bode well ahead of a visit to fortress Anfield.
Salah matched Suarez's Premier League record of 31 goals in a single campaign on Saturday and stopping their former team-mate over two legs may prove a step too far for Roma in their first appearance in the last four since they lost to Liverpool in the 1984 final.