Without Erling Haaland due to injury in recent weeks, the reigning champions have needed their other attacking options to step up to compensate for the absent Norway goal machine.

In recent fixtures, it's been Ghana's Antoine Semenyo, scoring the winner against Leeds United in late February, before following that up with the opener in the disappointing 2-2 draw with Nottingham Forest earlier this month.

With the Black Star benched against Newcastle for Saturday's Fifth Round tie, Marmoush was handed a starting brief, charged with leading the line and replacing Haaland's absent goal threat.

He didn't disappoint.

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Savinho's equaliser had cancelled out Harvey Barnes' opener by the time Marmoush fired City into the lead two minutes after the break. Nico O'Reilly was unable to control a menacing cross from the right by Matheus Nunes, and the Egypt international was a willing recipient of the loose ball, firing home emphatically into the roof of Aaron Ramsdale's net from close range.

Newcastle rang the changes to find a way back into the match, but in the 65th minute, Marmoush killed the contest, again following excellent work from Nunes.

The power Marmoush can generate with such little backlift, coupled with his lithe agility, is reminiscent of Jermain Defoe or City great Sergio Aguero, with the combination giving the Egyptian an unpredictability and deadliness on the edge of the box that few in the Prem can match.

Neither goals were indicative of a player struggling for form this season, yet Marmoush delivered a performance that belied his struggles at City during this testing campaign, with the 27-year-old a constant threat and lethal presence in the final third.

Newcastle will be sick of the sight of him; seven of Marmoush's 14 City goals have come against the Magpies, with the forward appearing to enjoy the Midas touch when up against Eddie Howe's side.

This was his second double of the season -- the first came against Newcastle in another 3-1 victory for City last month -- and sends Guardiola's side through to the FA Cup quarterfinals, where they've been rewarded by a home tie against Liverpool on April 4.

By this point, Haaland will likely be back leading the line, but Marmoush's mini renaissance in recent weeks suggests he has a big role to play during the final months of the season.

The attacker has five goals in his 11 appearances since the Africa Cup of Nations, compared with one in his 15 outings for the Sky Blues before the tournament.

He showed flashes of his instinctive finishing, dangerous pace and intelligent movement during the biennial showpiece in Morocco, even if it proved to be a frustrating competition for Egypt.

However, it may have had the unexpected bi-product of shaking Marmoush into life during a season in which he's largely looked a shadow of his Eintracht Frankfurt self.

A late bloomer, the 27-year-old scored 15 goals in 17 Bundesliga outings during the first half of the 24-25 season -- following on from 12 league goals the year before -- and hit the ground running after signing for City in a £59 million deal last January.

He immediately looked a danger on his debut against Chelsea, and opened his account for City against -- you guessed it -- Newcastle, with an emphatic hat-trick in mid-February last year.

He scored four in five consecutive matches between mid-March and mid-April, but would only hit one more before missing seven games with a knee injury sustained in September.

In truth, he's taken his time to return to anything close to his Eintracht form, with a City exit -- both Aston Villa and Tottenham Hotspur were named as potential suitors -- rumoured in January.

Suggestions that he won't be long for Eastlands continue to linger -- Barcelona are monitoring his situation according to The Athletic -- although his recent form may prompt a rethink from Guardiola.

Certainly, the Spaniard appeared particularly delighted when Marmoush's second goal, a fearsome strike from range that left Ramadale with no chance, and later gave the attacker a heartfelt embrace.

"I'm very happy for Omar Marmoush," Guardiola told BBC Sport after the match. "His second goal was magnificent.

"To beat Newcastle, you need a top performance - especially in the FA Cup, and he's a top-class striker, extremely clinical in front of goal."

Marmoush, alongside Semenyo, should be exactly what City need during the final stretch of the season as they look to compete on four fronts.

Their lack of consistent goal threat throughout the team has been one of the reasons why Arsenal have been able to keep such a tight grip on top spot.

At one point, with Haaland comfortably out in front in the scoring charts with 13 goals, no City player had more than one goal. Indeed, their second highest 'goalscorer' was Burnley's Maxime Estève, who scored two an goals against the Citizens in late September.

Since then, Semenyo and, latterly, Marmoush, have begun to find their goalscoring boots.

Longer term, Marmoush and Guardiola may need to have a tete-a-tete at the season's conclusion to determine whether player and club are best served by remaining together.