Electric Jeremy Doku is threatening to leave Jack Grealish in the dust at Man City - he must start the Manchester derby

Lots of players need a bedding-in period at City before coming good. Grealish had a pretty disappointing first campaign before understanding what Pep Guardiola wanted from him and putting it into action in his second season. Nathan Ake was a bench-warmer for his first two campaigns before turning into a steely defender.

But Doku has adapted straight away and made an instant impression following his €65 million (£56m/$68m) move from Rennes in August after being signed as a replacement for Saudi Arabia-bound Riyad Mahrez.

After a quietish debut against Fulham, the Belgian produced a stunning performance at West Ham. He ravaged Vladimir Coufal all game, scoring a wonderful goal to pull City level in an eventual 3-1 win, bursting down the left wing, twisting his way inside and finding the far bottom corner.

In a lively first-half display he crafted a glorious opportunity for Erling Haaland, which the Norwegian somehow managed to waste.

Despite that breakthrough match, Doku was then used sparingly by Guardiola. He started on the bench against Red Star Belgrade but had to come on before half-time due to the injury to Bernardo Silva, while he was sacrificed early in the second half against Nottingham Forest after Rodri was sent off.

He was a substitute against Newcastle in the Carabao Cup although given Guardiola fielded a second-string team, maybe that was a compliment. He started the next game at Wolves and was one of City's best players in their shock 2-1 defeat.

He was only given 18 minutes against RB Leipzig but swung the game around in City's favour, coming on when the game was tied at 1-1, setting up Alvarez's goal and then combining with the Argentine to score on the counterattack and seal the 3-1 win, showing his blistering pace and producing a composed finish.

In 10 appearances and only six starts, Doku has two goals and two assists - a solid return for a young player still feeling his way into the best team in Europe.

Part of the reason why Doku has been such a revelation at City is that he offers something completely different to his team-mates. Most City players have been shaped by academies, where youngsters are coached so thoroughly and moulded into identikit players.

City assistant coach Juanma Lillo, writing in The Athletic during last year's World Cup, decried the homogenous nature of modern footballers, which he admitted to be partly responsible for. "Everything is globalised now. At club level, if you go to a training session in Norway and one in South Africa, they’ll be the same," he wrote.

"'Look inside to find spaces outside’, ‘pass here, pass there’. The good dribblers are over, my friend. Where can you find them? I can’t see any. We don’t even realise the mess we’ve made."

Doku, however, is a breath of fresh air. He is a thrilling dribbler, unpredictable and a nightmare to defend against. While he joined the academy of Anderlecht aged 10, he supplemented his education with plenty of games on the streets, which explains his wild style.

"I learned to dribble on my own," he told Man City's official magazine. "I was always outside, playing with a football practising but nowadays, you see kids do that less and less and you don’t see as many kids playing on the street with a ball any more.

"They maybe play, but in their home or garden and I don’t think that’s good because I learned on the street against other kids. Street football was where I honed my skills."

The strange thing is that Doku is the opposite type of player to Grealish, his main rival for a starting position. Grealish used to be a free, marauding spirit until Guardiola coached his individualistic tendencies out of him.

Once famed for his twisting dribbles and scorching strikes from distance, Grealish is now an expert in hugging the touchline and holding the ball up, slowing the play down to give his team-mates time to get forward.

When asked about the two players after the Brighton game, Guardiola talked through their contrasting skillsets.

"He's an exceptional winger, so smart and defensive, intuitive to get the ball and after, he has the quality to go one against two and get to the byline for the first goal and the many actions he had," the coach said of Doku. "I’m really, really pleased about his impact since he came to us and he will be a star for many years to come in this house."

On Grealish, he offered: "Jack is more controlled. He doesn’t have this one-against-one speed but the control, the assists, he has always had."

Grealish made a quiet start to the season and was then ruled out for a month with an injury against Sheffield United. Since returning he has not managed to have much of an impact and is clearly not yet at the level Guardiola expects him to be.

He was a late substitute at Wolves, did not come on at all against Arsenal and started on the bench against Brighton before replacing Doku late on. Guardiola admitted that he expected more from Grealish this season, while being at pains to point out his contribution last season.

“He’s one of the players who we couldn’t have won the treble without. But yeah, we need him," he said. "I spoke a few times with him and in the future we need him… and, step by step, he is going to get to his best form, his best rhythm to help us because the season is so long.”

Grealish and Doku both started against Young Boys in the Champions League and the England midfielder was City's best performer overall. He started on the left wing but came inside far more often than usual and was at the heart of the team's best moves, even though he did not participate in any of the goals.

Whether to pick Grealish or Doku seems to be Guardiola's big dilemma heading into the derby at Old Trafford. It seems unlikely that he would start both players again just four days after a European night, although it is not out of the realms of possibility that, as against Arsenal, he fields neither.

If the coach views the derby as being a tight game where his side will be under pressure amid an intimidating atmosphere, opting for the more experienced Grealish and the control he brings makes sense.

But United are not nearly as strong as Arsenal and Erik ten Hag's side have looked vulnerable in almost every game this season. They were ripped to shreds by Brighton and Galatasaray and only snuck past Brentford, Sheffield United and Copenhagen. Put simply, the derby is the ideal game for Doku and his trickery.

United are still also missing their strongest defensive full-back in Aaron Wan-Bissaka, and Diogo Dalot - who Doku would be coming up against - is not known for his discipline at the back. The shortcomings of United's only fit left-back, Sergio Reguilon, are well known, offering an attractive route for Doku to explore should he wish to swap to the right wing.

The Belgian has already dazzled at the London Stadium, unlocked Leipzig and blown Brighton away. It's time to unleash him on enemy territory.