Charlton Athletic saw signs of what was to come from Conor Gallagher when he was on loan at The Valley during the 2019/20 season.
Most Addicks would admit they did not know an awful lot about the young midfielder when he joined the club on loan from Chelsea in August 2019, but Charlton boss Lee Bowyer was optimistic about the signing at the time.
"He's an exciting young player," Bowyer said.
"He can put his foot in, create, score and has a bit of everything, so I'm over the moon to have him through the door."
Gallagher became part of a club that had just been promoted from League One via the play-offs, and he was making his first real foray into senior football, so it was far from guaranteed that he would adjust to life in the Championship quickly.
However, the 19-year-old quickly showed that he was more than capable of holding his own in the second tier, and Charlton supporters got to see the emergence of a player who would go on to play at the top level.
Charlton Athletic struck brief Conor Gallagher gold after Chelsea decision
Conor Gallagher
After making his debut from the bench during Charlton's opening day victory against Blackburn Rovers at Ewood Park, Gallagher went on to start 25 of the Addicks' next 26 league games, with his only omission from the squad being due to suspension after picking up five yellow cards.
He scored in three of his first four starts for the club, with well-taken finishes against Stoke City and Brentford at The Valley, as well as a goal in a 2-2 draw at Barnsley.
In October, he scored in back-to-back games with the opening goal in a draw with Fulham at Craven Cottage and an incredible long-range effort in a 3-0 win at home against Derby County.
His last Charlton goal came at home against Cardiff City in November, but it was not just his output that made him so effective under Lee Bowyer.
Gallagher's relentless pressing, work rate, and combativeness combined with his ability to look after the ball after he won it back made him a key cog in Charlton's side during the first half of the 2019/20 season, and it is those attributes that have enabled him to go on and represent his country and feature regularly in the UEFA Champions League.
Charlton Athletic suffered from Conor Gallagher exit
The Valley, Charlton Athletic
Chelsea made the decision to recall Gallagher in January 2020, before sending him back out on loan to the Addicks' divisional rivals Swansea City later that month.
While Charlton suffered relegation back to League One in Gallagher's absence, the Swans were competing at the opposite end of the table and reached the play-offs.
The Addicks suffered a number of injuries to key players, and also had to finish the season without top scorer Lyle Taylor after he decided not to play after the COVID break, but there is no denying that Chelsea's decision to recall Gallagher was a key factor in Charlton's relegation.
Charlton supporters got to see glimpses of what was to come from a player who has commanded more than £70 million in transfer fees, played for a few huge clubs, and represented England on the international stage.
However, given the fact that Charlton would return to League One, Addicks supporters will always wonder what could have been if Gallagher stayed put for the campaign's duration.
The dynamic midfielder went on to enjoy Premier League loan stints with West Bromwich Albion and Crystal Palace before eventually starring for Chelsea and Spanish giants Atletico Madrid - and he's now recently returned to English shores by sealing a move to Tottenham Hotspur.