Leeds United are looking for their third manager in less than year after the sacking of Jesse Marsch.

But they are 17th, above the relegation zone only on goal difference after 20 games this campaign, with Saturday's 1-0 defeat by Nottingham Forest leading to Marsch's dismissal on Monday.

Why did Marsch fail? Who is best suited to take over? And what do they need to do to keep Leeds up?

For a section of supporters it was from the beginning, because he was not his predecessor Marcelo Bielsa.

The Bielsa supporters found it difficult to accept Marsch even though the club's position in the Premier League was parlous with a dozen games to go when the Argentine was sacked.

Others were adamant that an American coach would not work, while the majority, especially after securing last-day survival at Brentford, remained sceptical but open to the idea that he had earned his chance to start this season.

Losing Raphinha to Barcelona and Kalvin Phillips to Manchester City were blows, but reinvesting the money to buy Tyler Adams, Marc Roca, Rasmus Kristensen, Brenden Aaronson, Luis Sinisterra and Wilfried Gnonto was a clear sign that the club were backing their man.

The squad was arguably stronger. But as the games passed the narrow style Marsch was trying to implement failed to produce consistent performances, attractive football or results.

Marsch, a likeable, well-travelled and educated man whose elaborate management speak could sometimes confuse supporters, who were increasingly failing to see theory in practice.

Like Bielsa he did have to cope with significant injuries to experienced players - Stuart Dallas, Patrick Bamford and Adam Forshaw in particular - and the inability to purchase an experienced left-back to compete with Junior Firpo, who struggled for form and fitness, seemed short-sighted on the club's part.

There were glimpses of what might have been with a stunning 3-0 win over Chelsea in August. But only two more league wins were to follow, including a late winner at Liverpool in October on a night which many thought would be his last in charge after the crowd had turned on him and the board following awful performances and results against Leicester City and at home to Fulham.

He survived against the odds and the board gave him the World Cup break to imbue his footballing philosophy in his squad, but three points from 18 on the other side of it have left United in a relegation battle, which Marsch said they were not involved in after what he called "a complete performance" in the 2-1 loss at Aston Villa three weeks ago.

Fans saw and thought differently. After almost a year in charge it seemed beyond him to coach the squad to its potential, which by January included a record signing in Georginio Rutter, Austria defender Max Wober and Juventus midfielder Weston McKennie on loan.

Ultimately, the club's place in the top flight, a huge investment and a pending takeover by minority shareholders San Francisco 49ers Enterprises from majority shareholder Andrea Radrizzani were all jeopardised.

And so decisive action was taken following the defeat at Nottingham Forest. Chief executive Angus Kinnear and director of football Victor Orta delivered the news in person to Marsch at the club's Thorp Arch Academy after he had taken training for the final time.

Radrizzani is understood to be flying in to join Orta and Kinnear to continue the search for Marsch's successor during a week that includes two matches against bitter rivals Manchester United.

There is an initial shortlist of head coaches who they have already begun interviewing and it is hoped that an appointment can be made before Sunday's fixture at Elland Road.

Indeed, Radrizzani suggested in a tweet on Tuesdayexternal-link evening that the new man could be in place as soon as Wednesday morning, if not before.

Rayo Vallecano's Andoni Iraola is understood to admired by Orta. The former Athletic Bilbao defender, who played under Bielsa, has done a stunning job at Rayo, who are defying the natural order in Spain by sitting fifth in La Liga.

When Iraola was asked about interest from other clubs, he played his achievements down. "Football is about the players - we, the coaches, are not as important," he said. "It's the players who make us seem like we are the best and I am fortunate enough to have players who are showing their level."

Carlos Corberan, who took Huddersfield Town to last year's Championship play-off final and could well repeat the feat with West Bromwich Albion this time around, is also linked. Not least because he was at Elland Road prior to and during the initial part of Bielsa's reign as he worked as both under-23s head coach and first-team assistant to help United to promotion.

It would be foolish to rule him, or anyone out, at this stage but the feeling is he is not the club's first choice.

Supporters would like an ambitious appointment and that inevitably means names like Mauricio Pochettino being mentioned but he, Rafael Benitez and Steven Gerrard are not in the early reckoning.

Burnley's Vincent Kompany would certainly appeal. His playing experience in the Premier League with Manchester City and his coaching debut at Anderlecht have helped him to charge the Clarets to the top of the Championship.

The attacking third should not be an issue for United, who have a plethora of talent despite losing top scorer Rodrigo for up to eight weeks with an ankle injury.

Bamford is back fit, and with Gnonto, Rutter, Aaronson, Sinisterra, Crysencio Summerville and Jack Harrison there is plenty of fire power to score the goals required to ensure survival.

Defensively, United have looked too easily exposed with a frantic pressing style often leaving them short at the back when possession is lost, allowing opponents to unpick them easily, even when the Whites have been in advanced positions.

The tactics needs to change to allow best use of the width that exists in an exciting crop of players, rather than funnelling the play through the middle of the park.