Allegations of refereeing bias are nothing new when it comes to the bitter rivalry between Real Madrid and Barcelona.
Claims of perceived partiality in favour of the sworn enemy have peppered El Clasico's rich history, but two of the most experienced protagonists on either side of the playing divide have dragged this particular battleground into the era of social media and 24-hour news.
Whenever a controversial call falls Madrid's way, Barcelona centre-back Gerard Pique cannot resist tweeting about it. When Pique tweets about refereeing decisions during Madrid games, Los Blancos captain Sergio Ramos cannot resist firing back via the nearest available microphone.
These winners of Euro 2008, Euro 2012 and the 2010 World Cup with Spain are grown adults over the age of 30, yet their capacity to be cordial was a well-worn talking point during the recent international break, given a season of relentless back and forth.
The reunion passed without colourful spats, but the pair were back at it in Clasico week, when Madrid benefited from a particularly generous offside call for hat-trick hero Cristiano Ronaldo as they knocked Bayern Munich out of the Champions League.
Pique's views on such incidents are so well known that he was able to send internet chatter off the charts simply by tweeting: "…"
It was already sport's most famous ellipsis by the time Ramos was asked for his response to the offending punctuation post-match.
"Nothing new, I'm not surprised," he said, before pointing out Barcelona's historic comeback over Paris Saint-Germain in the last-16 had been aided by a particularly soft penalty call.
"He should rewind and look back to the PSG game and see if he thinks the same about the referees."
Spare a thought for Alejandro Hernandez Hernandez, the man in the middle of this tit-for-tat on Sunday and almost certainly on a hiding to nothing.
Hernandez Hernandez might have failed to award Barca a goal when the ball clearly crossed the line during a 1-1 draw against Real Betis in January – don't think for a second Pique will have forgotten – but outside of such freak occurrences, where does the balance of power lie when it comes to more everyday refereeing decisions? Is the bias Blanco or Blaugrana, or should Pique, Ramos and the rest stop fretting?
Penalties
Since the 2008-09 season in LaLiga, Barcelona have been awarded 76 penalties – more than any other side, barring Real Madrid with 81.
Before Pique cries foul, Barca have conceded nine fewer spot kicks than Madrid during the same period thanks largely to his old adversary.
Inauspiciously leading the way for penalties conceded in LaLiga over the past nine seasons is a certain Sergio Ramos, with a remarkable 11. By comparison, Pique has prompted the referee to point to the spot on three occasions.
The Barcelona defender would be sure to roll his eyes upon learning Cristiano Ronaldo has won 17 penalties since moving to LaLiga, although Neymar only arrived at Barcelona in 2013 and has already been awarded 14 in the top flight.
Lionel Messi has won eight across the same period, fewer than the likes of Diego Costa, Fernando Llorente and Aritz Aduriz, and only one more than team-mate Andres Iniesta.
Cards
For a man seemingly so keen to dive in when inside his own box, Ramos has an unsurprisingly hefty disciplinary rap sheet – 93 yellow cards and eight red have the Madridista again leading the way where a mid-table spot would, for once, be far more respectable.
Pique's tally of 61 yellow and five red see him compare favourably, at least until the LFP start dishing out cards for Twitter posts.
Overall, Madrid have had 44 players sent off and 751 booked since 2008-09, with Barcelona on 620 yellows and 25 reds. Most recently, and crucially when considering this weekend, was Neymar's early bath at Malaga two weeks ago. Atletico Madrid fall neatly between the two heavyweights with 36 dismissals.
Barcelona's opponents have been punished with red cards 59 times over the past nine campaigns - five more than Madrid have benefited from and teams need only tread more carefully against Sevilla (66 reds for opponents).
Fouls
Outside of those big calls, Barcelona fare the best from whistle to whistle. No team has won more fouls (5,033) or conceded fewer per game (11.8) since 2008-09.
Real Madrid's 4,808 fouls won brings them in below Malaga, Espanyol and Athletic Bilbao, while they are punished on average 13.12 times per match.
Overall, the statistics do not point towards the kind of conspiracy Pique claims, but do not expect that to ruin his or anyone else's mischief. This is El Clasico.
And so, over to the man who has awarded five red cards and seven penalties in 15 games this season, while presiding over seven home wins, five away wins and three draws.
Good luck, Senor Hernandez Hernandez – you'll need it.
