SUNDERLAND’S tortuous pursuit of Lamine Kone finally came to an end this evening when the centre-half completed a £5m move from Lorient.

But the Black Cats will have to beat off fierce competition from both West Ham and Aston Villa if they are to sign Arsenal full-back Mathieu Debuchy for the remainder of the season.

Kone was finally confirmed as a Sunderland player yesterday evening after signing a deal that commits him to the Stadium of Light until 2020 and taking over the vacant number 23 shirt on the Wearsiders’ squad list.

Sunderland had agreed two previous deals for Kone, only for talks to break down on each occasion as Black Cats officials failed to agree personal terms with the 26-year-old and his representatives.

As recently as last Thursday, Sam Allardyce was claiming Sunderland’s interest in the centre-half was “dead”, but talks were resurrected over the weekend after Sporting Lisbon declared a desire to sign Sebastian Coates on a loan deal, with a view to a permanent transfer in the summer.

Coates’ potential departure left Allardyce with a defensive hole to fill, and rather than looking elsewhere, the Black Cats boss opted to make renewed contact with Lorient officials.

Sunderland’s original £5m offer was once again deemed acceptable, and Kone was finally able to agree personal terms at the Academy of Light.

“Strengthening our defensive options was a priority for us, and Lamine is a player that has impressed me when I’ve seen him play,” said Allardyce. “He is big and strong – attributes you need to play in central defence in the Premier League – and his arrival will give us healthy competition for places in a key position.”

Kone is Sunderland’s fourth signing of the transfer window, following Jan Kirchhoff, Dame N’Doye and Steve Harper.

Confirmation of his arrival should speed up Coates’ exit, with the Uruguayan set to join Sporting Lisbon for the rest of the season, with an agreement in place for a €5m permanent move in the summer.

That would represent a profit of more than £1.5m for a player who joined Sunderland from Liverpool last summer, and who made 14 Premier League starts before falling out of favour at the end of last month.

Coates has not been involved in the Black Cats’ last three league games, with Allardyce preferring John O’Shea and Wes Brown at centre-half in the absence of the injured Younes Kaboul.

The Sunderland boss has made strengthening his defence a key priority this month, and has held a series of discussions aimed at signing Debuchy on loan for the rest of the season.

The former Newcastle United defender has been frozen out of the first-team picture by Arsenal boss Arsene Wenger, and has made just two Premier League starts this term.

He is desperate to leave the Emirates in order to enhance his chances of making the France squad for this summer’s European Championships, and Allardyce is keen to add him to the Sunderland ranks as an alternative to Billy Jones, who has played in the majority of his side’s matches this season, and DeAndre Yedlin, who could make an early return to Spurs as the Black Cats look to cut short his loan deal.

Allardyce knew he was likely to face competition from Aston Villa, with former Lyon boss Remi Garde having also made contact with Debuchy in an attempt to persuade the 30-year-old to move to Villa Park despite his club’s position at the foot of the table.

However, the situation has been further complicated by additional interest from West Ham, who are looking for a full-back after Carl Jenkinson suffered a knee injury that will keep him out for the rest of the season.

The Hammers have already signed Sam Byram during the current transfer window, but Jenkinson’s injury has forced Slaven Bilic to assess his options once again.

Jenkinson was on a season-long loan from Arsenal, and Bilic is understood to have raised the possibility of taking Debuchy as a replacement while his original loanee recuperates at Arsenal’s training ground.

One outgoing deal from Sunderland went through yesterday, with midfield outcast Charis Mavrias joining German second-tier side Fortuna Dusseldorf.

Mavrias, who joined the Black Cats from Panathinaikos in 2013, has joined Dusseldorf on loan, but given that his contract is due to expire in June, he has effectively already played his final game for Sunderland.