Jose Mourinho was the master against the man who was once his mentor as Chelsea moved to within two wins of the Premier League title by beating Louis van Gaal's Manchester United.
This was a meeting of the big beasts of Premier League management - two personalities with an iron-clad confidence their critics portray as arrogance.
Chelsea's 1-0 win means victory at Arsenal and Leicester will bring the title back for the first time since 2010.
Returning United to the head of English football is part of Van Gaal's long-term plan, so the stage is set for another great managerial rivalry.
Will this be the new Mourinho v Ferguson?
Jose Mourinho's rivalry with Sir Alex Ferguson was built on mutual respect going back to the night at Old Trafford in March 2004 when the Portuguese made his famous sprint down the touchline as Porto knocked out United en route to winning the Champions League.
When Mourinho pitched up at Chelsea later that summer, Ferguson knew he was not dealing with a young pretender but the real deal, while the younger man knew nothing was to be gained by taking on the old street fighter in the mind games.
It was not theatre played out to the same undercurrent of animosity that characterised Ferguson's relationship with Arsenal manager Arsene Wenger (at least until the Gunners ceased to be serious rivals) and former Liverpool manager Rafael Benitez.
Mourinho also saved his more acerbic comments for Wenger, while his interplay with Ferguson was civilised.
The same more gentlemanly rules apply between Mourinho and Van Gaal. For now.
Given Van Gaal's previous work with Mourinho at Barcelona, their interaction may well be of the cordial variety - although both men will not take a backward step when it comes to defending their corner.
Chelsea hold the upper hand but Van Gaal will be intent on changing that. Watch this space as there may be fireworks to enliven the Premier League's scenery.
Watching a different game?
Mourinho and Van Gaal, understandably, had eyes only for their own teams at Stamford Bridge - but their respective verdicts were polar opposites.
The statistics were stark. If possession really is nine-tenths of the law then United flouted it after having the ball for 70.3% of the match. United made 665 passes to Chelsea's 284 but still lost - and yet there was still much for Van Gaal to admire..
Mourinho, on the the other hand, was only interested in the statistic created by Eden Hazard's goal, saying: "The game was exactly what we wanted and when you manage to play the game you want that is fantastic."
He made himself and his players sound like magicians as he claimed they were able to "make United's important players disappear".
Mourinho detailed the giant figure of Kurt Zouma to nullify Marouane Fellaini's aerial strength, such a potent weapon in United's renaissance, while Juan Mata and Ashley Young were subdued and only lasted 70 minutes.
He said: "It was difficult but less than you think. Control their direct football to Marouane Fellaini and control the wingers from making crosses on the inside foot."
Mourinho may also have been suggesting Van Gaal gave too much of a clue when he said: "When we know Wayne Rooney is playing in midfield we control his progression in to the box. Control set-pieces and don't give away direct free-kicks as they have three specialists."
And then the key: "Wait for a mistake and score a goal. We were able to make their important players disappear. Nobody saw them. They were in our pockets."
Correct - but only to a certain extent. For all the control Mourinho claimed Chelsea exerted on Rooney, he should have scored with an early chance and also missed with a header.
The meticulous Van Gaal may note Mourinho's game plan on his trademark clipboard for future reference - and his view hardly mirrored his opposite number's.
Van Gaal , who was well aware of the match stats, said: "I am very proud of my team. We played our best match of the season but in football you can lose a match even when you are the better team.
As with so many things, the truth probably lies somewhere in between - but do not bank on two such strong and entrenched characters conceding an inch of ground on their views.
Van Gaal can be an intimidating presence, an occasionally jovial outlook masking the very obvious fact his opinion is not to be trifled with or easily challenged.
Here at Stamford Bridge the Dutchman, who moved through the gears to Vesuvius level in an encounter with the fourth official when he felt Falcao had been fouled in the build-up to Hazard's winner, was in combative, feisty mood.
In his BBC Sport after-match interview, Van Gaal's emotions were on show, throwing questions back in a manner rarely seen so far this season, perhaps feeling the pain of defeat in a match he felt his side should not have ended empty-handed.
Van Gaal has fought shy on several occasions of measuring United's performances against others earlier in the season but here he had no hesitation - this was the best.
For Mourinho, it was more a matter of caution, playing down Chelsea's wild celebrations at the end. Not the celebrations of champions but of a team that had accomplished a vital mission on the road to becoming champions.
This was Mourinho the pragmatist, the realist.
"Football is not about 'ifs' it is not about 'almosts'," he said. "It is about mathematics. When the mathematics say it is done it is done but until that moment we don't celebrate."
Mourinho gave off an air of satisfaction, Van Gaal a sense of injustice.
Back to the future?
The pair have history and a knowledge of each other's methods that only adds to the future intrigue.
Mourinho was first schooled by the late Sir Bobby Robson then Van Gaal at Barcelona before striking out on his own, armed with their knowledge and his own style after a high-end apprenticeship.
Van Gaal was so impressed he allowed Mourinho to take training sessions at Barcelona and even take control for tournaments such as the Copa Catalunya before graduating to take charge of Benfica in 2000.
The most high-profile crossing of paths came in the 2010 Champions League final when Mourinho's Inter Milan beat Van Gaal's Bayern Munich 2-0 at the Bernabeu - when the pair's mutual respect was on show before, during and after the game.
Van Gaal recalled how Mourinho came to his attention when he took over at Barcelona in 1997 and the Portuguese had been a member of Robson's staff, saying: "Mourinho thought he'd been promised the youth academy job and even that he might be the next manager and hadn't been told.
"He was so angry and shouted so much about not being consulted that I was impressed. On that day he was a 'Special One' and because of that I hired him."
Mourinho says of Van Gaal: "He is a very, very good coach. We are both great coaches. It's what we were born to do."
So who will come out on top?
Only one winner this season and that will be Mourinho - but Van Gaal has increasing confidence in his own "process" and a transfer outlay that could reach £150m for targets such as Borussia Dortmund's German World Cup winner Mats Hummels will only add to that belief.
Eden Hazard is the jewel in Chelsea's crown while United still look to Wayne Rooney.
And for all United's planned summer spending, make no mistake that Mourinho will be watching his rivals' moves while plotting his own spectacular responses.
Mourinho and Van Gaal are in the luxurious position of possessing talented squads with financial power to add - although their respective styles and approaches will not change. The basis of the tactical approaches this season are likely to be maintained next.
Chelsea have the advantage of the stronger team, more set in its ways and totally attuned to its manager's demands.
United are catching up - but recent weeks have suggested the battle between the two old friends and adversaries will be joined even more intensely next season.