Charlton boss Alan Pardew made a third January signing on Sunday by swooping for Sheffield Wednesday's Madjid Bougherra.
The Addicks have agreed to pay £2.5million for the 24-year-old Algerian defender, who joined the Owls in the summer from FC Gueugnon.
Bougherra's move to South Yorkshire proved such a success that the club have managed to agree a huge profit for a player who cost only £300,000 a matter of months ago.
Wednesday had turned down Athletic's initial bid of around £1.3million earlier in the month.
Charlton boss Alan Pardew, meanwhile, will hope that the centre-half, alongside fellow transfer-window additions Ben Thatcher and Zheng Zhi, will help his side win their ongoing battle with relegation.
As the FA Cup fourth round drew most attention 26-year-old midfielder Adam Bolder was the only other player on the move, swapping Championship leaders Derby for relegation candidates QPR for an undisclosed fee.
Elsewhere, Manchester United chief executive David Gill was forced to stave off suggestions that Real Madrid might tempt winger Cristiano Ronaldo into a summer move to Spain.
United manager Sir Alex Ferguson has already issued a 'hands-off' warning to the Bernabeu club following rumoured interest in a mega-money transfer.
And Gill insisted that, even if Real made an approach, club owner Malcolm Glazer would never sanction the deal.
'As (Arsenal manager) Arsene Wenger has said on many occasions, clubs aren't banks,' said Gill. 'We are there to put on entertainment and play a top-class team.
'There is no point having £35million or £45million if you can't replace that talent. At 21, Ronaldo has had a great season and the best is yet to come.
'If we did get a bid, I would tell the Glazer family. But I know the conversation would be very brief because it would be turned down immediately.'
Gill also admitted the Premiership leaders have virtually no chance of signing Owen Hargreaves before the transfer window shuts on Wednesday night.
The England midfielder has been subject to a reported £20million bid from the Old Trafford club this month, but Gill told BBC Radio Five Live: 'I can confirm we are interested in the player and we have been since last summer but at the moment Bayern Munich aren't willing to sell him and we will have to leave it at that.'
Championship promotion favourites Birmingham have been accused of failing to honour a verbal agreement allowing Matthew Upson to leave the club if a satisfactory offer was received.
The player's agent, Barry Neville, claims the 27-year-old was told by Blues he could quit St Andrews after four years if any interested clubs met their valuation - and he insists West Ham's recent £6million bid should have enabled talks with the Hammers.
He told the Birmingham Sunday Mercury: 'Matt is disappointed after having been told he could leave Birmingham for a certain amount - and what has been offered has gone way past that.'
Hearts head coach Valdas Ivanauskas has admitted Paul Hartley and Craig Gordon are both on the verge of being sold.
Neither featured for their club in Sunday's draw at Rangers, with the Gers themselves said to have made an offer for midfielder Hartley while Gordon is wanted by several English clubs.
Asked if Gordon's switch could be completed by the transfer deadline on Wednesday, Ivanauskas told BBC Sport: 'I hope.'
On the players' omission at Ibrox the Lithuanian added: 'I can't say too many words, all I can say is that it was football business, especially with Paul Hartley.'