No sooner had Borussia Dortmund waved off one American soccer phenom in Christian Pulisic, the Black-Yellows have already teased another in 16-year-old Gio Reyna.

Pulisic won't be forgotten in a hurry. Joining Dortmund on a Croatian passport at 15 and debuting in the Bundesliga less than two years later, the Hershey native tore up the script for American soccer hopefuls in Europe.

A five-year stint threw up all manner of league and international best-marks for a player widely believed to be the greatest his country has ever produced.

It's hard to disagree, although that theory could be about to be tested by Dortmund's new American kid on the block.

"There are a lot of well-known American players nowadays" said Dortmund CEO Hans-Joachim Watzke.

"Christian is the captain of the national team, but we have a very interesting young player, Giovanni Reyna.

"He's a big, big talent. I think he will do a lot for American soccer in the next five or 10 years."

Watch: Christian Pulisic - Made in the Bundesliga

Watzke may have to revise his forecast. Despite assigning Reyna to their U19s team, Dortmund took the youngster on their summer 2019 US tour - not as a marketing ploy, but to gain some invaluable first-team insight.

He played in wins over Seattle Sounders and reigning European champions Liverpool, chipping in with an assist for Paco Alcacer in the latter fixture, before enjoying a run-out in the 4-1 rout of Serie A side Udinese.

Less than a month in, Reyna is already ahead of the Pulisic curve.

"Giovanni is one of the world's best midfield talents in his age group," said Dortmund youth coordinator Lars Ricken. "He has exceptional technique and is a real team player.

"You don't just make signings to win the junior Bundesliga title, though. The club has a responsibility to the player and his family when you take them out of their social environment at such a young age.

"We only consider bringing in youngsters from abroad when we're 100 per cent sure that the player has the potential to play for the first team."

Watch: Catch a glimpse of Gio Reyna doing the business against Liverpool in pre-season

Reyna's top-level credentials were apparent from a young age.

"He used to dominate at U9s soccer in the park, when he was five," recalled Gio's father, Claudio, who played professionally for the likes of Bundesliga duo Bayer Leverkusen and Wolfsburg, Manchester City and the USA.

His mother, Danielle, played women's soccer in the US and Germany, but it was his late brother, Jack, who was the youngster's greatest muse.

"People assumed I trained him, but it was his brother, Jack," Claudio, a 114-time USMNT international, told Sports Illustrated. "He played with him and fought with him.

"Jack would go in goal and let him shoot - not always let him win, though, that’s for sure. And Gio fought and fought, and that’s why he played. That’s who he wanted to be."

Tragically, Gio lost his older brother to glioblastoma - an extremely rare and aggressive form of cancer - on 19 July 2012.

The evening after Jack died, he told his mother: "I'm never going to be a good soccer player now, because my big brother taught me everything."

Happily, he was wrong.

Gio was just nine when his brother, Jack, passed away, but he had the strength to pursue his soccer dream with New York City FC. - imago/ZUMA Press

In April 2017, Gio was named Player of the Tournament as his New York City FC team won the Generation Adidas Cup, a tournament for MLS U17 teams.

A month later, he inspired the US U15 national team to gold at the prestigious Torneo Delle Nazioni in Italy, registering four goals and as many assists. He was still only 14.

Amidst a bidding war from some of Europe's top clubs, Reyna remained with NYCFC, where his father holds the position of sporting director.

After a strong 2017/18 campaign with the New York U18/19s - in which he scored 13 goals in 17 appearances - Reyna moved to Dortmund in summer 2019, laying down a marker with a sensational solo goal on his U19s debut.

Exploiting his rangy gait to drive through the midfield at pace, BVB's newest transatlantic talent left TSG Sprockhövel defenders trailing his wake, audaciously nut-megging one before rounding the goalkeeper with the composure of a seasoned pro.

"He's much more of an athlete than I was, much more of a goal scorer," says Claudio, who operated in midfield over the course of his 14-year career.

"He's very technical and has a good feel for the game. He has a great free kick and can strike a ball well. Danielle was a great runner - and he's a runner."

Gio's talents have not gone unnoticed in his homeland.

His first ad campaign with endorser Adidas presented him as one of US soccer's beacons of hope after their failure to qualify for the 2018 FIFA World Cup, and he has already trained at U23 level internationally.

As long as he doesn't switch allegiance - he was born in England, but joined Dortmund on a Portuguese passport thanks to his paternal grandmother - Reyna Jnr. could well be fast-tracked into the senior national team, à la Pulisic, if he can continue his inexorable rise in Germany.

"Giovanni is a huge talent," said Dortmund sporting director Michael Zorc.

"Almost every club in Europe was in for him, but Giovanni had us in mind very early on.

"Although he is still very young, the transfer came up because we needed someone in his position."

Reyna has scored one goal in eight caps for the US U17s. - imago/ZUMA Press

It is a need that arose, in part, because of Pulisic's move to English Premier League outfit Chelsea.

The US soccer sensation was no stranger to playing at a higher level for his age range, graduating as he did from the BVB U19s to the senior side in January 2016 at the age of 17, and taking his USMNT bow that same year.

Five years on, he leaves as the Bundesliga's youngest non-German goalscorer, the youngest to reach two Bundesliga goals, the youngest player to appear and score for Dortmund in the UEFA Champions League, and the youngest American to lift a major European trophy (the 2016/17 DFB Cup). And that's just at club level.

The youngest US player to appear in and start a World Cup qualifying match as well as the most precocious to score and tally a brace for the USMNT, Pulisic has set quite the bar - but records are there to be broken.

Step forward Reyna; the teenaged prodigy blasting through the US soccer talent stream with the potential to blow all and sundry out of the water.

Chris Mayer-Lodge