Before Serge Gnabry made his Arsenal debut, Arsene Wenger had already declared the German attacker as 'a great hope for the future.' Soon after, he became Arsenal's second youngest Premier League player. Now, at just 21-years-old, he's sealed a €10 million move to perennial Gunners conquerors Bayern Munich.
Three times in five seasons the two sides have faced each other in the Champions League, but if they play again in the next few terms, the former 'great hope' of Arsenal could be turning out for the visitors at the Emirates Stadium.
When he left Arsenal in August, few fans were sad to see him go. Despite the hype from Wenger and the early impact, injuries had held him back and saw him fail to live up to the early promise.
“Serge Gnabry is a great hope for the future, I rate him highly,” Wenger told Arsenal Player back in September 2012. “He is in the category of [Alex] Oxlade-Chamberlain and [Theo] Walcott — guys who have great power, great pace and good dribbling skills."
A month later, Gnabry made his debut as a 17-year-old before properly breaking into the first team squad the next season. He lined out against Bayern Munich in the Champions League, where he suffered the knee injury that cut his campaign short and meant he played no part in the entirety of the 2014-15 Premier League.
The setbacks did not deter Wenger, who still believed in Gnabry and sent him out to West Brom to gain first team experience. However, the German's time at the Hawthorns proved even more frustrating than at Arsenal. He played just 12 minutes in the Premier League under Tony Pulis, who told the Express & Star that Gnabry was not "at the level to play games" for the Baggies.
Before his injury against Bayern, Gnabry had been touted as a possible surprise inclusion in Joachim Low's Germany squad for the 2014 World Cup. When he left Arsenal for Werder Bremen, he had played just 11 Premier League games, playing 484 minutes of top-flight football in England.
The great hope looked hopeless.
But it was easy to forget that Gnabry had just turned 21 as he returned to his native Germany. He had just finished as joint top scorer for Germany at the 2016 Summer Olympics. Arsenal did not want him to leave. Wenger urged him to stay, but Gnabry needed a fresh start.
"We didn't want to get rid of Gnabry," Wenger told BT Sport . "We wanted to keep him. But he was in the last year of his contract. We were close to extending his contract, but finally he changed his mind and went to Werder Bremen. But I think we taught him a lot, and I think if you ask him, he would agree with that."
At Werder Bremen, he finally had the chance to be a regular starter for a club. He finally had the chance to show that he could live up to his promise, and that is exactly what he did as the move to the Bundesliga finally kickstarted his career.
Gnabry became the first Werder player in over 10 years to score 10 away goals in a season, helping Alexander Nouri's side finish eighth in the table. Gnabry's impact impressed fans and earned him that call-up from Low, where he scored a hat-trick on his senior international debut against San Marino.
The 21-year-old clocked the fastest speed of any Werder Bremen player during the season, topping out at 34.72 km/h. He netted 11 times in 27 league games and was thought of as the future of the club.
That was until Champions League clubs came knocking. With fourth-placed Hoffenheim interested in his signature, Gnabry activated a clause in his contract allowing him to leave after less than 12 months.
With a move to Julian Nagelsmann's side looking imminent, Bayern Munich swept in and signed a player who remains one of Germany's hottest young players — an astonishing five years after his professional debut.
With competition for places fierce at the Allianz Arena, a loan to Hoffenheim has been mooted, but either way, Gnabry is likely to play in the Champions League next season. After 20 years in the tournament, Arsenal will not feature next season and will be forced to watch one of their former stars of the future in action elsewhere, leaving Wenger and supporters kicking themselves for the one that got away.