Neymar's sensational €222million move from Barcelona to Paris Saint-Germain was undoubtedly the highlight of a transfer window also memorable for the deals that did not happen. 

Barcelona themselves were at the heart of one of them, refusing to meet Liverpool's €200m last-minute asking price for Philippe Coutinho, while Arsenal held on to Alexis Sanchez despite the Chile international entering the last year of his contract.

Here, we assess six of the biggest failed transfers of the window and assess whether the players involved will be welcomed back into the fold at their clubs.

PHILIPPE COUTINHO

Barcelona spent weeks trying to persuade Liverpool to sell Coutinho, seeing multiple offers rejected, only to then baulk at the Anfield club's deadline day demand for a whopping €200m.

Coutinho reportedly put in a transfer request to force through a move and it may be telling that despite not featuring for Liverpool this season, the 25-year-old was fit enough to play for Brazil on Thursday, scoring in their win against Ecuador.

How Coutinho responds to being priced out of his dream move to Camp Nou could be fascinating and handling him will be a major challenge for Reds boss Jurgen Klopp.

ALEXIS SANCHEZ

Arsene Wenger insisted throughout the window that Alexis Sanchez would not be sold despite being in the last year of his contract - and the Arsenal manager got his way.

Manchester City repeatedly tried to reunite Sanchez with his coach from Barcelona Pep Guardiola, only for a deadline day deal reportedly worth £60m to fall apart.

Arsenal attempted to bring in Monaco winger Thomas Lemar as a replacement for Sanchez but the France international rejected the switch so both players stay - for now at least.

ROSS BARKLEY

In contrast to Arsenal's handling of Sanchez, Everton manager Ronald Koeman was determined to sell Ross Barkley after the midfielder refused to sign an extension to his contract, which expires at the end of the season.

Barkley seemed poised to move to Chelsea on deadline day for £30m only for the player to pull out of the transfer, later claiming via social media he wants to get fit before considering his options.

Tottenham are reportedly lurking, but it is questionable how much football Barkley will now play ahead of a World Cup year, especially as Everton broke their club record to bring in Gylfi Sigurdsson.

VIRGIL VAN DIJK

Liverpool looked set to land Netherlands centre-back Virgil van Dijk early in the window, only to be forced into a hasty apology after being accused of tapping up the Southampton player.

Van Dijk handed in a transfer request and went public on his desire to leave St Mary's in search of European football but, despite the likes of Chelsea and Manchester City being reportedly keen, a late deal failed to materialise.

Southampton's new coach Mauricio Pellegrino will now hope Van Dijk can be persuaded to play, with the centre-back having been training alone.

ANTOINE GRIEZMANN

Manchester United were strongly linked with a move for France star Antoine Griezmann, but after Atletico Madrid's transfer ban was upheld the striker decided to stay in LaLiga.

Griezmann even signed a new contract, accepting it would be "dirty" to leave with Atleti unable to sign a replacement, but a switch to a bigger club still seems inevitable in the near future.

Atletico's transfer ban expires in January, but Diego Simeone will want to keep Griezmann until the end of the season.

DIEGO COSTA

Diego Costa is a handful for managers as well as centre-backs, with the Brazil-born Spain international threatening to go on strike at Chelsea.

Costa wants to rejoin former club Atleti, but their transfer ban has again blocked a move, with the striker upset at being told via text message by Blues boss Antonio Conte that he is no longer required at Stamford Bridge.

Despite Costa failing to report for training, Chelsea have named him in their Premier League squad, so perhaps there is another twist to come in this saga.