The transfer window is a little bit different this year, given the coronavirus pandemic, and deadline day for most of the top leagues in Europe has been shifted to Oct. 5. That means there's just one month left for clubs to make their moves.

Chelsea have already had a pretty busy window and spent over £200 million on players like Timo Werner, Hakim Ziyech and Ben Chilwell, while Manchester City had been chasing arguably the best player of all time, Lionel Messi, before he was forced to stay put.

But there's plenty of time left for other clubs to get involved. So which one player should the best teams be looking to land before the window slams shut?

Clubs are ordered by most pressing need, from biggest to smallest.

BARCELONA: Lautaro Martinez
Club: Inter Milan
Value: €100m

It would likely take a bit of financial magic to pull this off, given Barcelona's state of affairs, but Inter striker Martinez has been earmarked as the long-term successor for Luis Suarez and now could take on another role in the side once Lionel Messi eventually departs too. At 23, Martinez has a lot of potential to develop, and Inter's transfer policy to date suggests they would be open to taking ageing stars in part-exchange.

Barca still need a big lift in morale ahead of the new season, and the signing of someone like Martinez would do that.

MAN UNITED: Dayot Upamecano
Club: RB Leipzig
Value: €55m

Man United clearly want Borussia Dortmund winger Jadon Sancho but, with a fee of €120m, are struggling to work out a deal with the German club. Ajax's Donny van de Beek has arrived for around €45m and that should satisfy the desire for creativity in midfield, but United really need to strengthen in the centre of defence.

At 21, Upamecano is one of the best young centre-backs around and would be a stellar signing to sit alongside Harry Maguire. Sources have told ESPN's Mark Ogden that United have made the Frenchman their No. 1 target and they should really look to tie up a deal before other clubs start to get interested.

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ARSENAL: Thomas Partey
Club: Atletico Madrid
Value €50m

Arsenal have seemingly been craving a world-class defensive midfielder since Patrick Vieira departed in 2005. Lucas Torreira has done OK since he arrived in 2018 but looks keen to head back to Italy this summer, and Partey has all the attributes to be a success in the Premier League.

The 27-year-old has a €50m release clause in his Atletico contract which should make negotiations a lot easier, though the Gunners have yet to decide whether they are willing to spend before they raise funds by allowing players to leave. A €30m deal for Brazilian centre-back Gabriel Magalhaes is done, but that could mean there's precious little cash to use on other areas that need strengthening.

TOTTENHAM: Diego Costa
Club: Atletico Madrid
Value: €10m

Tottenham need a backup striker for Harry Kane, and Atletico Madrid are reportedly happy for Costa to depart this summer. He's still only 31 and would bring the combative element that manager Jose Mourinho has been trying to impart. OK, he might be somewhat disruptive and he'd certainly pick up the odd red card, but what better manager to take care of him than the man who did so at Chelsea.

Costa wouldn't be the main striker; he wouldn't play every game. But coming off the bench to worry defences with his aggression and strength in the final stages, the Spain international could win Spurs plenty of points.

CHELSEA: Gianluigi Donnarumma
Club: AC Milan
Value: €50m

It seems incredible that Donnarumma is only 21, given he's played over 200 games for Milan already, but he's still rated as one of the best young goalkeepers in the world. The Italian is entering the final year of his contract and has been linked with plenty of top clubs, though Chelsea makes the most sense as they are looking to move on Kepa Arrizabalaga this summer.

Kepa became the world's most expensive goalkeeper when he signed from Athletic Bilbao in 2018 for €80m but was dropped by Chelsea boss Frank Lampard at the end of last season as his form deteriorated. A straight swap, plus cash, would seem a good deal for both clubs, but Chelsea have already spent a lot this summer, so what's another €50m? Atletico Madrid stopper Jan Oblak is another option but, at €120m, is too expensive, while Edouard Mendy of Rennes is the cheaper option.

JUVENTUS: Raul Jimenez
Club: Wolves
Value: €80m

The Mexico striker has become one of the best in the Premier League over the past few seasons -- and arguably CONCACAF's finest -- and Juve need a replacement for Gonzalo Higuain, who is departing this summer. Jimenez scored 27 goals in all competitions last season and his signing has reportedly been given the blessing of Cristiano Ronaldo, who is understandably growing tired of shouldering the goal-scoring burden in Turin.

At 29, Jimenez has a good few years left at the top and is reaching his peak, so if Juve have players to offer in return to lower his price then they should think about it.

MAN CITY: Kalidou Koulibaly
Club: Napoli
Value: €80m

It was all about Messi but City didn't actually NEED to sign Messi. He's 33 and may well have found the physical challenge of the Premier League a bit different to what he's used to in La Liga. Now that he's staying in Barcelona, what City need is reinforcements in the centre of defence, and Koulibaly is perfect.

The 29-year-old Senegal international is as tough as they come and would be a perfect foil for Aymeric Laporte. He has good passing skills, fantastic reading of the game and would finally fill the void left by Vincent Kompany.

INTER MILAN: Tanguy Ndombele
Club: Tottenham
Value: €35m

Recent transfer windows have seen Inter Milan target Premier League players, and Tottenham midfielder Ndombele looks like he will need to find a new club after he told manager Jose Mourinho that he never wants to play for him again following a clash in June, sources told ESPN.

Reports suggest that Inter are ready to move on Christian Eriksen, despite only signing him from Tottenham in January, and Ndombele could replace him in midfield ... if the club are ready to go back to Spurs so quickly. At 23, the Frenchman has his whole career ahead of him and could be a real asset to Inter. Given his issues with Mourinho, he would also be available to sign for around half his club-record €60m fee.

PSG: Ricardo Pereira
Club: Leicester
Value: €35m

Leicester would be loath to lose another full-back (having let Ben Chilwell join Chelsea) but they have signed the versatile Timothy Castagne from Atalanta, so despite the fact Pereira has had a real impact in England since joining the club in 2018, they might be willing to let him go. The Portuguese suffered an anterior cruciate ligament injury in March, which means Leicester have had to get used to playing without him, and PSG could take advantage as he returns to full fitness.

PSG need to strengthen on the right side of defence and Pereira came third in the ESPN FC 100 ranking at the end of 2019, so he has the kind of quality that PSG need if they are to claim the Champions League trophy. Reports have claimed PSG are also chasing Arsenal's Hector Bellerin for around €30m.

DORTMUND: Jean-Clair Todibo
Club: Barcelona
Value: €25m

Dortmund need a central defender and Barcelona are looking to sell players. The one issue is that Dortmund have very little money to spend and would likely need to seek a loan move for Todibo, who impressed in the Bundesliga at Schalke last season.

The 20-year-old has bags of potential and that marks him out as a perfect Dortmund signing, given how they have done with Jadon Sancho, Gio Reyna and Erling Haaland, among others. At some point the club will need to find replacements for some, if not all, of those players, but right now they just need to land someone who can improve their defence. If they can't get Todibo, perhaps a move to bring 32-year-old Sokratis Papastathopoulos back from Arsenal (before he signs for Napoli) would work?

BAYERN MUNICH: Sergino Dest
Club: Ajax
Value: €25m

Having already landed their top transfer target in €55m Man City winger Leroy Sane, Bayern need to turn their attention to right-back. Dest has been a star for Ajax and they could get him for a decent fee before his price starts to increase. Alphonso Davies has proven to be a revelation, and the Canadian's development should offer the 19-year-old Dest all the evidence he needs to show his career could follow a similar path.

Bayern have also been linked with 20-year-old Norwich City defender Max Aarons, so it's clear that they are looking for youth over experience at full-back this summer.

LIVERPOOL: Thiago Alcantara
Club: Bayern Munich
Value: €30m

New Barcelona manager Ronald Koeman has insisted that the club sign Georginio Wijnaldum, sources have told ESPN. And that leaves the door open for Thiago to finally make the move to Anfield to replace him.

A €30m move for the Bayern Munich midfielder had looked like stalling, but if Wijnaldum leaves then Thiago can slot in perfectly. He has plenty of experience, desire and a winning mentality that should suit Jurgen Klopp's style of play. Liverpool were never going to spend big, or spend at all unless one of their first-team left first, so this seems like a great option for both player and club.

REAL MADRID: Edinson Cavani
Club: Unattached
Value: Free

Real have little money, so get ideas of a world-record move for PSG's Kylian Mbappe out of your minds for at least another year. Rennes teenager Eduardo Camavinga is their top midfield target, alongside Napoli's Fabian Ruiz, but will also have to wait until 2021, while any interest in Dortmund striker Erling Haaland could be put on hold for two years.

However, they do need a backup striker as €60m man Luka Jovic has struggled. They don't come much better than Cavani, and a one-year deal could be attractive to the 33-year-old, who has failed to secure deals with Atletico Madrid or Benfica since leaving PSG. Send Jovic on loan and Cavani can be a quality backup to Karim Benzema.