As swaggering stylists, fuelled by passion, fashion and riches, both clubs belong among the continental elite. And both are also attempting to end decades of domestic championship doldrums by swapping tradition for powerful cheque books and cosmopolitan squads.
In both cases, too, there is a strong cup-fighting spirit, an element of Forza Italia, as they revel in their footholds at the summits of Serie A and the Premiership. Two capital clubs, if you like, still swinging after all these years.
Next week, while Chelsea prepare to meet Valerenga, the Norwegian club now coached by the former national team chief, Egil Olsen, Lazio will be plotting the downfall of Athens' Panionios, managed by the former Liverpool midfielder Ronnie Whelan. Having beaten Helsingborg of Sweden and FC Copenhagen of Denmark, Gianluca Vialli's men will be confident of completing a Scandinavian hat-trick and then avoiding the Romans in the last four.
That is, of course, assuming Lazio - booming with talent and cash these days - avoid any slip-ups when Whelan returns to the scene of his greatest triumph as a player when Liverpool beat Roma on penalties to win the European Champions' Cup in 1984.
At that time, both Lazio and Chelsea were regarded as sleeping giants. Hung-over giants, some might say, with horrible fans too. Chelsea, until their FA Cup win of 1997, had previously not tasted success since 1970 when Peter Osgood and David Webb were in their pomp, on and off the field. Their sole title of 1955 had been forgotten.
Lazio, Italian Cup winners in 1958, won a Scudetto in 1974, but then fell dormant, particularly after being relegated for their part in the Milan match-rigging scandal of the early 1980s. Their fans, like Chelsea's "Headhunters" who congregated in the unlamented Shed at the same period, were infamous for their excessive ferocity and violence. The Curva Nord was their lair.
But that was back then. Nowadays, the main excesses at both clubs are financial. With Chelsea Village having come of age, the London club is, according to a recent listing of the world's richest clubs, seventh in Britain with a turnover of pounds 23.7m. Lazio were sixth in Italy and 19th globally with pounds 27.3m.
If that is not remarkable enough, like Chelsea, Lazio's recent surge to the top of Serie A - they took over for the first time since 1974 when a Sergio Conceicao goal beat Internazionale last Sunday at the Stadio Olimpico - has coincided with massive funding from the financier Sergio Cragnotti. Last May, Lazio became the first Italian club to float on the Bourse, Milan's stock market, a move which had stunning success and allowed the blue-shirted section of the capital to celebrate the spending of pounds 75m on new players in the run-in to the club's centenary in 2000.
Considering that Cragnotti paid only a reported pounds 15m to buy the club in February 1992, it is nothing less than astonishing that he has since then spent 10 times that amount on new players, Paul Gascoigne among them, as he attempted, like Chelsea, to buy his way to the title.
Indeed, the arrivals list for last September's Italian season kick-off was amazing. While Ken Bates and Vialli paraded Marcel Desailly for pounds 4.6m alongside such wonders as Albert Ferrer, Pierluigi Casiraghi (from Lazio, of course) and Brian Laudrup, Lazio's bespectacled Swedish coach Sven- Goran Eriksson was welcoming Marcelo Salas, Christian Vieri, Ivan de la Pena, Fernando Couto, Dejan Stankovic and Sinisa Mihajlovic.
A severe injury jinx struck down many of those Lazio leading lights but now, all that is forgotten. Vieri is back, Salas is scoring, the team is winning.
Conceicao's goal last week rocketed Lazio's share price from 9,000 lire, on Friday, to 15,000 on Monday - an increase of 50.4 per cent in the club's value on paper. In the last three weeks, the total valuation of the club has gone up by 75 per cent, or around pounds 72m.
It is little wonder, then, that Lazio were linked this week with a cool pounds 25m offer for Michael Owen, a bid hotly denied by Liverpool. And, no wonder too, that Eriksson, 51, is poised to sign a new contract, that Casiraghi aches in frustration that his cruciate ligament injury will keep him out of a Chelsea-Lazio "dream" final and that Lazio, of all the clubs in all the world, have recently opened two new centres of excellence: in Kansas City and China. Top that, Chelsea. Ciao.Reuse content