Some say Eden Hazard's goal against Liverpool in September 2018 was his best. It was all there in 12 seconds, featuring as it did, a nutmeg in the build-up, that swaggering insouciance as he strolled towards the flank before injecting speed into the attack, a drop of the shoulder and a thunderous finish into the far corner.
Others prefer the atypical left-footed rocket against Sparta Prague. The Liverpool goal had come in his final season at Chelsea with his exit all but inevitable. The goal against Sparta was the standout strike in his first. A spectacular introduction, all hope and optimism.
Most settle for those moments laced with schadenfreude. The late goal that bent into the top corner, ending Tottenham's title hopes in 2016. The one against Arsenal after bumping Francis Coquelin to the ground. Just the mere sight of Pablo Zabaleta on his backside.
His status as a Stamford Bridge legend is secure. Hazard was the genius behind two title wins. He brought joy and, importantly, he had fun doing it. When he left in 2019, the concern was how much he would be missed. Few considered Hazard might struggle too.
On Tuesday, he hopes to face his former club still waiting to ignite his Real Madrid career. It is almost two years since his €100m move was greeted by 50,000 expectant fans in the Bernabeu. Hazard is yet to show them what he can really do. Perhaps he never will.
The move to Madrid had long been mooted but his first season there was the worst of his professional career. Hazard set the tone by turning up significantly overweight for pre-season, not for the first time in his career. This time he was unable to make amends.
He was quick to acknowledge his failings. "It has been a season of adaptation," he said. "I will be judged on the second one. It is up to me to be in good shape next year."
But this second season has been even worse, persistent injuries preventing him gaining any momentum. Hazard was not fit until the end of October and injured again before November was through. Another brief and unproductive comeback was curtailed in January.
"It is hard when you have been playing 90 minutes for 12 or 13 seasons and suddenly you cannot do what you have always done," said an understandably sympathetic Roberto Martinez, his national team coach with Belgium. "It is kind of a shock."
Karim Benzema, who has stepped up to lead the attack in Hazard's absence, has been supportive too. "Eden has not had any luck since he arrived. I am sad for him. He is a top player who can help us a lot. He is sad because he wants to prove he is a star."
But this, of course, is the nub of the issue. Hazard would like to be the world's greatest player, but Cristiano Ronaldo, the old favourite in Madrid, needed to be. It is a key point of difference - one that Hazard himself has the self-awareness to appreciate.
"I often ask myself what I can do to become like Messi and Ronaldo and score 50 or 60 goals in a season," he once said. "I try, of course, but I realise that I will never be a true scorer.
"It is not in me. It is mainly mental.
"Sometimes I still think after a goal, 'That is enough'. I am not in search of records like some other players. If I can score between 15 and 20 goals each season, I will be very happy."
Hazard's ability put him into the top bracket and hinted at the possibility for more. The questions kept coming, not just to him but to coaches and team-mates. Could he go to the next level? It was never really fair. That requires talent, luck and pathological drive.
He is under no moral obligation to show the sort of single-minded determination that sets Ronaldo apart from even fellow professionals. And besides, that boyish charm is disarming.
His approach to the game was no great secret. Filipe Luis tells tales of Hazard playing Mario Kart minutes before kick-off. John Obi Mikel says he is the laziest player he ever played with. "While we were working, he was waiting for us to finish training, just standing there."
But when the injuries continue to hamper him, what once seemed charming can begin to grate. Hazard could yet become the most expensive acquisition in Real Madrid's history. Without the weekend heroics, his perceived aloofness is more awkward to indulge.
Perhaps that is why he finds himself on the path of his old heroes. "I learned a lot from Ronaldinho and Robinho," he once said. "Football is a tactical game and sometimes you have to be serious. But they taught me to always do it with a smile and have fun."
Nothing wrong with that. But Ronaldinho was 30 when he scored his last goal in a major European league back in 2010. Robinho's came for the same club - AC Milan - a few years later. He was 29.
It is partly psychology, but it also pragmatism. Hazard is a dribbler in his thirties, a winger who has found fame and fortune thanks to speed and trickery, outmanoeuvring opponents from a standing start. It is a difficult role to sustain in what is a young man's game.
The top 40 dribblers in the Premier League this season are all younger than Hazard. Those who stay at the top adapt. Ronaldo turned to physical attributes that Hazard does not possess. Messi is Messi, but even he leans more on his playmaking abilities now.
Hazard's reinvention is less obvious and unlikely to be an immediate concern. He will hope to regain fitness and recover the game of old, with targets that are eminently achievable. A tournament in the summer. A World Cup next year. More highlights to come.
But with Vinicius Junior, at 20, a decade younger than Hazard, lighting up the Champions League quarter-final against Liverpool in his absence, the age question comes into this when form and fitness are discussed. It is some time since the world saw Hazard's best.
Whether it will be seen again is no longer guaranteed when those fast-twitch fibres are failing. There can be a role for him, as Franck Ribery showed at Bayern Munich. But time flies and memories fade. Up against Chelsea, Eden Hazard will be hoping for a refresher.