When an teenage makes Real Madrid history in a crucial European match against Manchester City, it inevitably draws acclaim and attention.
During his maiden start in the tournament - and fifth game for the club - the young midfielder made a strong impression as the 15-time Champions League winners claimed a three-nil round of 16 first leg advantage at the Santiago Bernabeu.
The teenager, who also had his Real debut in the play-off round a month ago with a substitute appearance at Benfica, then assisted the Madrid side overcome the English champions in Tuesday's return to secure a quarter-final place.
Aged 18 years old, Pitarch became the team's youngest player to start twice in the Champions League's latter rounds, surpassing star Vini Jr's record by a week and a half.
This talent is the most recent to emerge from the club's academy and is rapidly cementing himself as one of the manager's most promising young players.
He joined Madrid from CD Leganes in the summer of 2023, having previously been with Atletico and Getafe's academies, and initially featuring for the Juvenil C team, where he rapidly created a positive impact.
He worked his way up to the B team and it was in a friendly match in which they played against the academy's first team, then managed by Arbeloa, where the youngster is said to have drawn the eye of the current Real boss, who replaced Xabi Alonso in the new year.
Reports would later describe the moment as "love at first sight," adding Pitarch stood out not only for his technical ability, but for the vitality, character and determination he brought to the side.
In the pre-season of 2025, ex-manager Alonso invited the youngster to train with the senior squad and awarded him minutes in pre-season.
However, it was Arbeloa's appointment that proved the defining moment in his development as he came on as a second-half replacement in each leg against Benfica that led to the clash with Manchester City.
"I have dreamed of this every night when sleeping, the first day I started playing football, every day you head to training and every day you play a match," stated the player after his first appearance.
"I've just achieved my dream with the greatest club in the world and in the top tournament."
Given a first start in La Liga against his former club - where he was for four years after arriving from Atletico in 2018 - he has retained his place for the following four as fitness issues to Bellingham and Dani Ceballos created an opening.
The teenager has taken it with performances that have defied his youth and experience.
"He is a very quick player, and you can see his capabilities," said the coach. "He is incredibly energetic, with great stamina, effort and movement."
Pitarch's mentality has also stood out to his coach.
"His greatest quality is his personality," continued Arbeloa. "He constantly demands the ball, and when pressed, he remains unfazed.
"I realize people are astonished to see him make his debut in a Champions League match, but he's playing because I had complete trust in him to do what he usually does.
"Thiago will continue to get chances with the main squad. It is delightful to coach a talent like him."
Pitarch was born in Fuenlabrada, in the Spanish capital's community, and grew up fully immersed in Spanish football, progressing through youth setups before entering Real Madrid's renowned youth academy.
He possesses both Spanish and Moroccan citizenship, giving him the option to play for both nations at the highest level.
According to Fifa eligibility rules, footballers may represent multiple nations at youth level without being locked in, with the final decision only binding once they appear in a competitive senior international match.
Pitarch has featured for Spain at youth level, representing both the under-19 and U20 teams, and participated in the 2025 Fifa Under-20 World Cup, where La Roja made it to the quarter-finals.
Nevertheless, he has not yet decided to any full national side, who are monitoring his progress with interest.
In a recent interview, Pitarch said: "I have not taken my ultimate choice so far. My situation is positive with the Spanish federation, but I'll make a decision in the near future."
This scenario mirrors that of other dual nationality talents such as Real team-mate Diaz and Barca star Lamine Yamal. While teenage Yamal opted for Spain, Brahim opted to represent Morocco.
For now, Pitarch's focus is on making his mark in the Madrid lineup and rewarding his manager's belief.
He played over an hour in the 2-1 win at the Etihad, which completed a 5-1 aggregate success and a last-eight matchup with the German champions.
His substitution by fellow youth graduate in Manuel Angel underscored the coach's confidence in younger players to help the club pursue trophies to come.
Following his impressive impact to date on the Champions League, the midfielder is expected to be a central figure in that.
"The manager treats me the identical way. We handle it very normally. I attempt not to overanalyze it excessively - I must earn my playing time on the field," he said following the win at Manchester.