A rough old week in the gilded life of Pep Guardiola has taken another turn for the worse.

First, the bombshell of Manchester City's guilty verdict compounded by details of their brazen disregard for Premier League rules as they built him a team to dominate.

Then, the Negreira scandal reared up again in Spain with 50,000 pages of evidence compiled by Real Madrid landing at UEFA on Thursday accusing arch-rivals Barcelona of making illicit payments to an influential referees' chief.

Maybe the timing is a pure coincidence. Maybe pure Madridian mischief.

Either way, Guardiola, the finest coach of his generation, finds his legacy under scrutiny like never before with demands raging for two of his three clubs to be stripped of the glittering array of titles he won.

The allegations in Spain are that Barcelona paid more than £7million in a series of payments over 17 years from 2001 to Jose Maria Enriquez Negreira when he was vice president of Spain's technical committee of referees.

Barcelona have repeatedly denied any wrongdoing, claiming the money was paid for scouting and technical reports provided by a company belonging to 81-year-old Negreira since the story broke in 2023.

At the time, Barcelona president Joan Laporta said: 'Let it be clear Barca have never bought referees and Barca never had the intention of buying referees, absolutely never.'

La Liga claimed they were unable to investigate because of the time elapsed since the alleged offences were so far in the past.

UEFA did launch an investigation although it appeared to be going cold until the matter resurfaced this year as Florentino Perez ran for re-election as president of Real Madrid with promises to get to the bottom of what he called 'the biggest scandal in history'.

On Thursday, UEFA issued a statement to confirm a 'substantial amount of documents' had landed at the door of its ethics and disciplinary inspectors and will be assessed.

Madrid-based sports papers Marca and AS splashed it across their front pages on Friday. Their Catalan equivalents gave the story less prominence.

Barcelona's response has been to point out that the proceedings have been ongoing since 2023 and had never been closed, and that they had complied with all requests to assist authorities.

The gist of the argument from Barca all along has been that nobody has offered any proof of sporting influence.

The allegations cover a period ending in 2018 when Barcelona-born former referee Negreira stepped down from the committee responsible for appointing match officials among other things.

Guardiola was head coach of Barca for four seasons in the heart of this era, from 2008 to 2012, during which he created a team generally accepted to be among the best to ever play the game.

With a youthful Lionel Messi sparkling at its heart, they won the Spanish title in three of Guardiola's four seasons and in 2011 swept the board winning every trophy they could, from La Liga and Copa del Rey to the Champions League, the Spanish Super Cup, UEFA's Super Cup and FIFA's Club World Cup.

The Negreira scandal relates specifically to Spanish domestic football but any lingering accusations that Barcelona tried to influence officials during this era will however chime with fans of English clubs.

At Chelsea, they will not forget the second leg of the Champions League semi-final at Stamford Bridge refereed by Tom Henning Ovrebo in 2009.

With the Blues ahead in the tie and well on top, Ovrebo resisted strong claims for what Chelsea boss Guus Hiddink later described as 'three clear penalties' and when Andres Iniesta equalised in stoppage time to send Barca into the final on away goals, Didier Drogba led the furious protests screaming 'disgrace'.

Chelsea defender Jose Bosingwa told Portuguese TV he thought the Norwegian referee had been 'bought'. Hiddink called it 'an injustice'.

Manchester United were beaten by Guardiola's Barcelona in the final in Rome, as they were again two years later at Wembley.

At Arsenal, they will recall Robin van Persie's red card at the Nou Camp in the last 16 tie in 2011, when Italian referee Massimo Busacca gave the Dutch striker a second yellow for taking a shot at goal one second after the whistle had gone.

'It is a joke,' fumed van Persie at the time. 'Frankly, embarrassing,' seethed Arsene Wenger.

There are many examples and it appears Real Madrid could have catalogued them all in their 50,000-page dossier.

Jose Mourinho, brought back by Perez for a second spell at the Bernabeu, will require no encouragement to fan the flames of the scandal.

Directly up against Guardiola's Barcelona for three years in his first spell at Real and for two more years as rivals in Manchester he thrives in a thickening plot, adept at the art of casting doubt.

After losing to Atletico last month, he seized his opportunity to lambast the appointment of the referee for the derby by the committee which no longer involves Negreira but will remain tarnished by association as long as these accusations continue to swirl.