The impact that Serge Gnabry had in North London on Wednesday, and has been having in Germany for more than a year, should send seismic shockwaves to Arsenal FC.
Of course, the four goals Gnabry scored in 35 minutes at the new Tottenham Hotspur Stadium shattered the Spurs, not Arsenal.
But think of it. This is a player the Gunners signed as a boy and sent back to Germany on the cusp of manhood. He was 16 when Arsene Wenger plucked him from Stuttgart for the Arsenal academy - and a month shy of his 21st birthday when he returned to Germany.
Arsenal barely gave him a chance. Even more discouragingly, he lasted less than half his intended year on loan at West Bromwich Albion. That Monsieur Wenger, the manager who had thrust other youngsters such as Cesc Fabregas into his team at the tenderest of ages, to give up on Gnabry was surprising.
That Tony Pulis, then the West Brom manager borrowed Gnabry in the first place, and then permitted him precisely 12 minutes of Premiership action in six months, would have shaken the spirit of any budding player.
Obviously, Gnabry was not Pulis's cup of tea. It should have been obvious to Wenger in advance because Gnabry is a subtle talent and Pulis is the most pragmatic of managers, a throw back to the up-and-at-em old English.
Undoubtedly, Gnabry had growing problems. He suffered a serious knee injury, and perhaps a crises of confidence in where he belonged. He is the son of an Ivorian father and a German mother.
But one expected Wenger to nurture him the way he had Thierry Henry and others. The swift movement was obvious in the teenaged Gnabry, so was the balance, the ability to move with the ball and shoot with either foot. Traits that Wenger coveted, and traits, one felt, that the manager would have relished drawing out.
How intriguing it must have been to observe Wenger watching on television the devastating 35 minutes of Gnabry destroying Spurs. The boy is now a man of 24, still learning, still living to some extent in the shadow of Bayern Munich's phenomenal striker, Robert Lewandowski.
But never mind Bayern, Germany's national team manager Joachim Low has described Gnabry as the first player on his team sheet whenever available.
Jogi Low is biased. His Mannschaft have struggled since its early capitulation at the 2018 World Cup and now relies heavily upon Gnabry's nine goals in 10 international appearances.
Don't misunderstand me. I rate Wenger among the most enlightened football men ever to work in England. He transformed attitudes and habits. He cherished, to a fault, the beautiful game. He persuaded gifted but shy players to grace our league.
One wonders now if the "Wenger Out" brigade who burned money to trail disparaging messages in the sky, are satisfied that they hounded away the man who gave them ballet in boots?
Yes, towards the end it faded. Yes the over-indulgence in Mesut Ozil became an overpaid millstone, a wonderful talent who appeared to lose industry and appetite once Wenger signed off Ozil's bloated £300,000 (S$510,000) weekly wage.
Unai Emery is no Wenger. He made it clear last week that he will not tolerate idleness, and the only options for Ozil are to show some hunger in training, or be shown the exit even if that means Arsenal paying a huge part of his salary to play elsewhere.
Arsenal glimpsed the future in the Europa League when the 18-year-old Brazilian, Gabriel Martinelli, scored twice. But come Sunday against Bournemouth, will Emery dare to go again with the Brazilian?
Maybe, but probably not in the starting XI. For Emery has a pragmatic streak, an emphasis on trying to stop the opposition play, a reliance on energy as opposed to artistry.
Arsenal crushed Bournemouth 5-1 the last time they met in London but there is little between them either in goals or points this season. Bournemouth has a striker, Callum Wilson, coveted by Manchester United, and Emery will ask his midfield to double up to help out the Gunners' dodgy defence against him.
Only then might Pierre-Emerick Aubameyang, Wenger's last signing, get support to chase an Arsenal record dating back to Dennis Bergkamp in 1997-8. Bergkamp started off that season with seven goals in the first seven games.
Aubameyang can match or surpass that today. Auba is much more in the Thierry Henry mode of swift, instinctive predator, but he is feeding off scraps rather than the mellifluous creativity of the bygone Wenger era.
