LAMINE KONE has signed a new five-year contract committing him to Sunderland until 2021 – but the Black Cats will still face a renewed battle to hold on to the centre-half when the transfer window reopens in January.

Kone put pen to paper on his new deal yesterday, bringing a temporary end to a saga that dragged on for the majority of the summer and briefly threatened to result in the centre-half’s departure to Everton.

With his representatives claiming they had been promised a new deal by former Sunderland boss Sam Allardyce, Kone was heavily linked with a possible move to Merseyside, and while the defender insists he did not submit a formal transfer request, he was unable to face Middlesbrough in last month’s Wear-Tees derby despite David Moyes questioning the severity of his back injury.

Sunderland turned down two offers from Everton, the second of which was worth around £22m, with Moyes insisting he did not want to lose the Ivory Coast international.

Contract talks were kick-started again at the start of last week, and Kone has agreed new terms that are understood to represent a considerable increase on the wage structure that was originally in place when he signed from French side Lorient for around £5m in January.

“Lamine is an important player for this club, and I made that clear to him from the outset,” said Moyes.  “He has only been playing in the Premier League since January, but in that time we have already seen what he is capable of.

“The challenge for Lamine now is to build on what has been a very positive introduction to English football, and to continue to improve and grow as a player.”

Kone’s current importance can hardly be overstated, with Monday night’s defensive collapse against Everton having highlighted the deficiencies of some of those around him in the Black Cats’ backline.

Papy Djilobodji made a succession of errors as Romelu Lukaku scored a second-half hat-trick, but the former Chelsea youngster is likely to keep his place at the heart of the defence as Jason Denayer lacks experience following his loan move from Manchester City while Moyes does not appear to rate veteran John O’Shea.

Kone is unquestionably Sunderland’s leading central defender, but yesterday’s developments are unlikely to draw a line under the ongoing speculation about his long-term future.

Everton are expected to make a renewed attempt to sign him when the transfer window reopens in January, with Ronald Koeman regarding him as a potential partner for Ashley Williams in the next few seasons.

Other Premier League clubs would also be interested if Sunderland were to signal a willingness to sell, but at least yesterday’s deal will ensure the Black Cats secure the highest possible price if they are tempted to cash in at some stage in the future.

Moyes accepts a club like Sunderland could have to sell one or two of their leading assets at some stage in order to fund future improvements, although he will still be extremely reluctant to lose Kone unless he thinks he can recruit an adequate replacement in the same transfer window.

The Sunderland boss also faces a decision over Jan Kirchhoff, with the influential midfielder in the final year of his current deal after only signing an 18-month contract when he moved from Bayern Munich in January.

Since then, Kirchhoff has developed into one of Sunderland’s key performers, and Moyes would ideally like to tie the German down to a new long-term deal too.

Whether or not that is possible remains to be seen, with Kirchhoff sure to have his admirers both in England and his homeland if he enters January without having penned a new contract.