Firmino and Lukaku occupy opposite poles of the modern-striker spectrum
They may wear Nos. 11 and 10, respectively, but they are false nine and genuine nine, Red and Blue, who sum up the differences between Liverpool and Everton. Roberto Firmino is the striker who isn't really a striker. Romelu Lukaku is the out-and-out centre-forward. The Brazilian cost £29 million, the Belgian £28 million. Jurgen Klopp has pronounced himself amazed Liverpool managed to sign Firmino at such a cost. Ronald Koeman rather undiplomatically suggested Lukaku might outgrow Everton and gravitate toward Barcelona or Bayern Munich.
If it rendered Lukaku part of the problem at Everton when the disconnect between fans and manager grew before Tuesday's win against Arsenal and where the sense was that potential was going unrealised, Firmino has been the solution for Liverpool, the man who epitomises a team of tireless runners defined by their attacking midfielders. When they meet on Monday, he may be utilised on the left while Divock Origi leads the line in the reshuffle caused by Philippe Coutinho's injury, but there is little doubt Firmino is now Liverpool's first-choice striker.
He is the attacker who is the first line of defence, leading the pressing game from the front. In contrast, Koeman is trying to cajole Lukaku into following suit. As the manager conceded, it does not come naturally to his top scorer. He saves energy whereas Firmino burns it. Recent statistics showed the Belgian runs 2.8 kilometres fewer in a game (8.7 to 11.5) compared to his Brazilian counterpart. Lukaku, according to Sky Sports statistics, covered less ground on average than any other outfield player in the Premier League last season, just 8.6 kilometres per game.
His threat can be sporadic, but also lethal. Whereas Firmino has only once topped 12 goals in a season, Lukaku only dropped below 16 in 2011-12, when he was a little-used Chelsea substitute. But whereas Lukaku has outscored Firmino this season, Liverpool have outscored Everton. There is a separation of responsibilities at Goodison Park, a collective commitment to finding the net at Anfield. Firmino is in a bunch of potential scorers, along with Origi, Coutinho, Adam Lallana, Sadio Mane and the prolific penalty-taking left-back James Milner; Lukaku shoulders a heavier burden.
Firmino helps Liverpool be fast, fluent and fluid, so that the man who appears in the striker's position at any given moment might not actually be the supposed striker. Everton have been more static and disjointed in the past three months, looking for connections and alliances. They thought they had one in Yannick Bolasie and Lukaku, both of Congolese origin, with the winger setting up four goals for the forward, but the summer signing's season-ending injury deprived them of it.
Lukaku's link-up with Ross Barkley has felt awkward, a reason why the Merseysider has been dropped of late, whereas Firmino's alliance with Coutinho seems symbiotic. Indeed, Firmino has flourished as the furthest man forward to such an extent that he often appears less effective when deployed on the flanks now.
Without really being a striker, he is nonetheless one in keeping with Liverpool's traditions. Ian Rush pressed in the 1980s, as those who stress it is no revolutionary idea have pointed out. Fernando Torres did so more recently. Luis Suarez ran around frantically. Unlike their neighbours, Everton have often had a target man and, even if most, unlike Lukaku, wore the No. 9 shirt that is iconic at Goodison, he belongs to a lineage including Duncan Ferguson, Graeme Sharp, Bob Latchford and Dixie Dean.
But despite his footballing ancestry, the "baby Drogba," as Lukaku was nicknamed in his younger days, appeared the prototype of a modern striker, a towering figure with the pace to stretch defences, giving him the physical attributes to hold the ball up or counterattack at speed. Factor in his ability to shoot with either foot and a goal-scoring record that consistently places him among the most prolific forwards in the country, he seemed perfectly equipped for an era of one-striker formations.
Then along came Firmino. Draw a spectrum of the Premier League's leading strikers and Firmino is at one end, with another rebranded winger Alexis Sanchez his closest companion, and the slower, taller Zlatan Ibrahimovic at the other. The South Americans spearhead the new breed, while the Swede is in the vanguard of the conventional. Yet Lukaku figures nearer Ibrahimovic than Firmino on the scale. He is 23, and Firmino threatens to make him look an anachronism.
But an eloquent individual has it in his power to script a telling retort. Lukaku has scored three goals in the past three Merseyside derbies at Goodison Park. He is the specialist scorer to Firmino's multi-functional athlete, the selfish striker against the selfless runner. The comparatively new-style lone forward may be looking old-fashioned because of a blur of movement in the Liverpool attack, but Lukaku deals in a timeless currency: goals.
Richard Jolly covers the Premier League and Champions League for ESPN FC. Twitter: @RichJolly.