The 20-year-old Real Madrid midfielder is surrounded by angry Barcelona players near the corner flag.
He looks up to see a direct red card brandished against a backdrop of flags for Catalan independence and enraged home fans spewing abuse.
All but 120 away fans in the biggest crowd of the season cheer.
Beyond the febrile stands, rises the sleek communication tower above Barcelona's Olympic Stadium, representing an athlete holding the Olympic flame. But the spirit inside the football stadium is not remotely Olympian.
Anything that hinders the enemy goes: the ground rules of any major football rivalry. Barcelona are inferior to their great rivals and are losing 1-0 with 35 minutes to play. Now they have a chance against a team reduced to 10 men.
The crowd smell blood and the red card triggers a slew of anti-Madrid songs which slate Jose Mourinho. Except Real Madrid's first-team coach is not present.
This is the reserve team derby, the mini clasico between Barcelona B and Real Madrid Castilla and a crowd four times the average have turned up to see it.
The first teams of Real Madrid and Barcelona meet frequently. They will play tomorrow in the first leg of the Copa del Rey semi-final, again in February in the second leg and again in March in the league.
With the Spanish Super Cup, that will be six times this season, just like last term. They may also meet again in Europe, as they did in 2011.
The reserve sides have bobbed around the divisions ever since, spending more time in the regional third tier and because they are from cities 600 kilometres apart, they have not met.
When Pep Guardiola was appointed the coach of Barca B in 2007, he found them in Spain's fourth tier.
"We'd go to little Catalan towns where everyone wants to shoot you down," said Sergio Busquets, who rose through the B team like many of his teammates.
"I remember one game at Rapitenca in a tiny stadium in the south of Catalonia near the Ebro Delta. The people were shouting all kinds of abuse at us, as were the other players. Most of us were 18, 19, playing against 34-year-old men who wished they had played for Barca."
Guardiola led them to promotion before taking the first-team job and elevating Busquets and Pedro with him. Another promotion followed in 2010 under his replacement Luis Enrique.
That saw Barca join Villarreal as the only club with a second team in the second level, giving their young players valuable experience playing against hardened professionals for established clubs such as Celta Vigo or Valladolid in front of big crowds.
It bridges the gap between the reserves and the first team, a gap which is a chasm in countries such as England, where reserve-team football is watched by a few hundred and played by 20 year olds.
In Spain, two teams from the same club are not allowed to play in the same division. Segunda A is thus the ceiling for Barca B and Castilla, but when Villarreal's first team were relegated last season, their reserves also went down - despite finishing 12th.
Barca B, by this time coached by the former Barca and Spain midfielder Eusebio Sacristan after Enrique went to Roma in 2011, finished eighth. They were joined this season by a Castilla side which has spent all but two of the last 15 years in the third division.
It was not always so. In 1980, as a second division side, they reached the final of the Copa del Rey, qualifying for the European Cup Winners' Cup where they were eliminated by the English FA Cup holders West Ham United. Reserve teams are no longer permitted to enter the cup.
The two clubs have contrasting attitudes to their second-string sides. Barca's is a final step before the first team, the hop across the road from the 17,000 capacity Mini Estadi to the 98,600 Camp Nou mother ship.
The Catalans' first team kick off against Osasuna 15 minutes after the mini clasico, where seven of the starting XI are former B team players. On the same day, Madrid's first team beat Getafe 4-0.
Not a single Madrid outfield player came through their B team.
A poster on the exterior of the Mini Estadi features an image of Lionel Messi and Busquets with the message: "Come to the Mini and see the stars of the future".
It is no lie; it would be in Madrid's case. Barca's Masia youth system is famed for producing footballers who make their first team. Madrid's Fabrica is not.
The players of either team are paid similar amounts of around €3,000 (Dh14,800) a week and the average age of both teams hovers around the 20-year mark, but Madrid's players are unlikely to be playing first-team football at the Bernabeu in the future.
The odds are against most of the Barca B players, too.
"It's still a huge step up," said Arnau Riera, Messi's captain when the Argentine played for Barca B in 2005. "I trained with the first team and the speed they pass is mesmerising.
"You are taught in the same 4-3-3 formation at every level in Barca, to play the same way, but there are few mistakes in the first team."
At Madrid, the formation of the first team is different from that of the reserves and Mourinho has been critical of the calibre of the players coming through.
He said that after the reserve striker Alvaro Morata played at Levante earlier this season. Morata did well, but faced with getting in a side ahead of Karim Benzema, Gonzalo Higuain and Cristiano Ronaldo, was soon back in the reserves.
Maybe, like the former Madrid reserve regulars Juan Mata and Roberto Soldado, he will have to go elsewhere for first-team football.
With such a rich pedigree, scouts from 24 clubs, from Everton to Borussia Dortmund, are in the 12,050 mini clasico crowd. They watch Morata give Madrid the lead after 35 minutes and dominate. Their vocal fans, most of them from areas of second and third generation Spanish immigrants which surround Barcelona, antagonise the biggest home crowd of the season (Barca B average 3,500) by singing Viva Espana and waving the Spain flag.
Madrid's superiority ceases when the midfielder Alex - the brother of their captain Nacho - receives the 56th-minute red card.
Barca score three, two from the Argentine Sergio Ajaujo, on a two-year loan from Boca Juniors, for whom he made his first-team debut at 17. Barca have an option to buy him. Their third is scored by the league's top scorer Gerard Deulofeu, an 18-year-old blond-haired Spaniard who joined the Catalans aged nine and is tipped to make the first team.
The win means Barca stay fifth having beaten former top-flight teams such as Hercules, Sporting Gijon and Villarreal. Castilla slip to 16th, two points above the relegation zone.
Not quite mirroring what is happening in the Primera Liga, but nevertheless the mini clasico serves merely to underline that Madrid currently cannot match Barca in any football department.