The 26-year-old was substituted in the ninth minute of his country’s World Cup qualifier with Burkina Faso – which finished as a goalless draw – in Ouagadougou on Tuesday.

Marmoush, who joined City from Eintracht Frankfurt for £59m in January, was hurt following a robust fourth-minute challenge.

City said initial scans in Egypt indicated Marmoush would miss Manchester United’s visit to Etihad Stadium on Sunday (16:30 BST).

The club confirmed Marmoush “will now return to Manchester for more assessment and to begin his rehabilitation”.

Marmoush initially played on after receiving treatment on the field, but was replaced by Osama Faisal shortly afterwards.

He has scored eight goals in 28 appearances for City.

City boss Pep Guardiola could be short of options in attack, given summer signing Rayan Cherki is currently sidelined with a hamstring injury and England attacking midfielder Phil Foden missed the defeat by Brighton before the international break.

Marmoush, who joined City for £59m from Eintracht Frankfurt last month, clearly has a long way to go before he can get close to the authentic Liverpool version – but broke his scoring duck in style after four matches without a goal.

Just 13 minutes and 54 seconds separated Marmoush’s opener – when he took advantage of Kieran Trippier’s failure to read a long ball downfield from City goalkeeper Ederson – and his third as he swept home first time from 10 yards.

In between, Marmoush applied a neat finish to Ilkay Gundogan’s defence-splitting pass into the penalty area. This was the fourth-quickest Premier League hat-trick by a City player – Sergio Aguero netted the fastest with a nine-minute treble in 2015.

Substitute James McAtee scored City’s fourth following a flick-on from stand-in skipper Erling Haaland.

Even with a side shorn of defensive trio Manuel Akanji, Ruben Dias and Nathan Ake, it was a throwback to the ‘old’ City of recent years and the perfect warm-up to Wednesday’s do-or-die Champions League return with Real Madrid.

Guardiola will hope the knock Haaland sustained four minutes from time which triggered his early exit from the game does not prove to be too serious.

For Newcastle, defeat at Etihad Stadium was a familiar experience – they have now lost 16 successive matches at this ground and failed to score on their past six visits.

The 25-year-old has agreed a contract until June 2029, with add-ons rising to £4m.

Marmoush has scored 15 goals in 17 Bundesliga games this season, second only to England captain Harry Kane’s 16 for Bayern Munich.

“Manchester City is one of the biggest clubs in the world over the past 10 years, so it was not a question,” Marmoush said.

“It’s a pleasure and an honour for me and my family to be representing Manchester City. It makes them happy; it makes me happy that my dreams are becoming a reality.

“The last two seasons have been great, but it is just the beginning for me.”

City have also signed 19-year-old Brazilian defender Vitor Reis from Palmeiras for £30m and Uzbekistan defender Abdukodir Khusanov from Lens for £34m in the January transfer window.

Marmoush, who has played as a striker, a number 10 and a winger, said: “On the pitch I am fast, good on the ball, I try to see where the spaces are and exploit the spaces – and I’m dangerous.

“My main strength I would say is that I always want to win – that is from a character point of view.”

City director of football Txiki Begiristain said Marmoush has “outstanding pace and awareness” and that his versatility is a “really valuable asset”.

Marmoush began his career with Wadi Degla in the Egyptian Premier League, before signing for VfL Wolfsburg in 2020.

He had loan spells at FC St Pauli and VfB Stuttgart before his 2023 move to Frankfurt, for whom he scored 37 goals and made 20 assists in 67 games.

Sources have told the BBC a verbal agreement has been reached between the clubs but the transfer has not yet been completed.

The 25-year-old Egypt international has scored 15 Bundesliga goals this season.

Marmoush joined Eintracht on a free transfer from fellow Bundesliga club Wolfsburg in 2023.

Manchester City are expected to soon complete the signing of Brazilian teenage defender Vitor Reis, who is flying in for a medical to complete his move from Palmeiras.

The club are also interested in signing Juventus left-back Andrea Cambiaso, though City sources say talks are not as advanced as reports in Italy are suggesting and there is no guarantee a transfer will be completed this month.

Cambiaso, 24, joined Juventus from Genoa in 2022, and this season has made 25 appearances, scoring twice and providing two assists.

The Premier League champions are yet to confirm they have signed Uzbekistan defender Abdukodir Khusanov, after agreeing a £33.6m fee with Lens for the 20-year-old.