To say that Guiu hit the ground running after breaking into the Barcelona first team would be a major understatement.

The La Masia graduate made an instant impact after coming on in the 79th minute of Barcelona's La Liga match against Athletic Bilbao in October 2023, scoring just 33 seconds later to earn Xavi's team a 1-0 victory.

His path to the senior side was much less straightforward, however. Impacted by multiple growth spurts during his teenage years, the frontman was not always a regular starter at youth level.

"He missed a lot of games," Albert Capellas, Barcelona's former assistant director of youth football, told Sky Sports earlier this year. "He could not train.

"What happens at a lot of clubs, if you cannot train or play, maybe you have to leave. [But] at Barcelona, we know the level of the players, we give them time."

The Catalan club's patience played into Guiu's hands. He made a further six appearances for the senior team in 2023-24, scoring again in a 3-2 defeat by Royal Antwerp in the Champions League.

"Marc Guiu is a finisher," added Capellas. "[He] is not a player who has unbelievable skills one against one, who can dribble past players. He is another type of player, but he is exceptional in his position. He has the nose to score goals."

Barcelona are believed to have attempted to remove Guiu's modest £5m release clause from his contract by offering an extension, but Chelsea activated that clause in June before signing the youngster on a five-year deal, with an option of a further year at Stamford Bridge.

Guiu may have been given a helping hand with two of his three goals against Shamrock Rovers, but he displayed the predatory instinct of a seasoned frontman to capitalise on those first-half errors.

His third of the evening - a header from Madueke's cross - was almost nonchalant.

"It was instinctive," said Cole, reflecting on the 18-year-old's treble. "I liken him to [former Barcelona, Liverpool and Uruguay striker] Luis Suarez.

"I'm not saying he's Suarez right now, but he has that instinct and bravery.

"This kid can score goals. He can be a big star for this club."

Kiernan Dewsbury-Hall, scorer of Chelsea's third goal, was just as effusive in his praise of his young team-mate.

"I've never seen anyone press like him," he said. "He never slows down."

Despite appearing in all Chelsea's Conference League games this season - including the qualifying play-off against Servette - Guiu's chances have been limited domestically.

He has not played in the Premier League since the Blues' 2-0 loss to champions Manchester City in their opening game, when he replaced the injured Nicolas Jackson.

He was a second-half substitute in the Blues' 5-0 Carabao Cup victory over Barrow - but their fourth-round exit at the hands of Newcastle denied Guiu further opportunities to impress in that competition.

It has been a different story in Europe, however, with Guiu averaging a goal every 47 minutes in the Conference League league phase - the best record in the competition.

His six goals have come from 19 shots, earning him an impressive conversion rate of 32%.

Jackson's rich vein of form in the Premier League and Christopher Nkunku's goalscoring exploits in the Conference League may have delayed a proper first-team breakthrough, but Maresca suggested it is only a matter of time before the teenager is given a chance to shine on a more regular basis.

"He is a bit unhappy as Nicolas and Christopher are doing well," the Italian said after Thursday's win.

"When you are a nine and another nine is doing well, it is a matter of being questioned. It's important that they work hard day-by-day.

"Then they [will] get a chance."