A London rivalry which barely needed any added spice - and then Jose Mourinho and Frank Lampard entered the fray on opposite sides.
Once united in blue, two-time Chelsea boss Mourinho took over at Spurs just over a year ago and has since come face-to-face with Lampard on the touchline three times.
Chelsea did the double over Tottenham in the Premier League last season, in what was a difficult first six months or so in the job for Mourinho.
Frank Lampard and Jose Mourinho will lock horns again in the Premier League on SundayInsurance Loans Mortgage Attorney Credit Lawyer
The pair, who used to be in tandem at Chelsea, argued on the touchline back in September
But Spurs got the better of their rivals in the Carabao Cup in September, via penalties, in a match marred by the two managers squabbling in the first-half.
This season, Tottenham are off to a flyer and heading into weekend are top of the tree - but Chelsea, two points further back, have the opportunity to leapfrog them this afternoon.
But which players would get in a combined XI and what star names would miss out? Sportsmail takes you through the team, based on players available for Sunday's contest.
Hugo Lloris (Tottenham)
In the summer, this was a straightforward pick. Chelsea's then-No 1 Kepa Arrizabalaga was short of confidence and, essentially, could not play a game without making an error.
But the £22million signing of Edouard Mendy has turned around Chelsea's fortunes at the back, with the ex-Rennes keeper - who plays international football for Cameroon - keeping five clean sheets in his first six games amid an upturn in form for Lampard's side.
That being said, Tottenham currently have the best defensive record in the division, having conceded just nine goals, and their captain and World Cup winner Hugo Lloris is a major factor in that solidity.Insurance Loans Mortgage Attorney Credit Lawyer
Tottenham captain Hugo Lloris has been as solid as a rock for his team so far in this campaign
Reece James (Chelsea)
This was not an automatic pick, but given his explosive start to the season, Reece James is the first pick in defence.
The 20-year-old has thrived in a three-month period which has seen him not only usurp club captain Cesar Azpilicueta but also make his international debut for England, impressing with his crossing ability and defensive capabilities for both club and country.
Though Matt Doherty is back in the running, as well as Serge Aurier being on decent form, James gets the nod at right back.
Reece James has broken through to be a regular starter in the Chelsea first-team this season
Kurt Zouma (Chelsea)
Amid varying defensive partners, Kurt Zouma has been a constant for Lampard and seems to have found some consistency alongside his obvious potential.
The 26-year-old has actually been at the club for six years but he now, finally, seems to have found his feet in west London.
He has already scored twice and his aerial dominance has been crucial in the Blues' unbeaten run which stretches to 10 games in all competitions.
Kurt Zouma has been Frank Lampard's regular at centre back and has finally found his feet
Eric Dier (Tottenham)
Having permanently shifted from defensive midfield to centre back under Mourinho, Dier has become a commanding presence at the back for Spurs.
Though he has made a few mistakes at the back for England, he has been defensively dominant in virtually every Spurs match he has played in the Premier League.
In fact, it is telling that out of nine goals conceded, three of those came against West Ham, when the England international was absent with a minor injury. Mourinho has always rated the 26-year-old and looks to have made a leader of Dier.
Eric Dier has been present for all but one of Tottenham's Premier League games so far
Ben Chilwell (Chelsea)
This was a tricky selection and a choice between two summer signings who have hit the ground running at their respective clubs.