Southampton's Luke Shaw resists a move to Chelsea or Manchester United in this transfer window That is unlikely to stop Chelsea and Manchester United continuing to pursue their interest and making a bid, if not in this transfer window then during the summer. There is confidence at Southampton, however, that Shaw will remain their player not only after this window but also next season. Although Southampton are well aware of the interest from Chelsea and Manchester United, there has been no formal bid from either and, having sold Alex Oxlade-Chamberlain to Arsenal for £15 million in August 2011 when he had never played outside League One, they will be aware that Shaw's value is probably in excess of £20 million. Chelsea's longer-term need for a successor to Ashley Cole has been brought into sharper focus by Jose Mourinho's decision to play César Azpilicueta at left-back for much of the season. They could also offer understudy left-back Ryan Bertrand as a sweetener in any deal. A concerted effort to sign Shaw now looks likely in the summer, with Mourinho expecting only limited movement within his Chelsea squad this month. The situation with Juan Mata will almost certainly be tested by Paris St-Germain but Chelsea's attitude will be shaped by the player's wishes. Mourinho said on Monday that the club had an "open door" should Mata wish to hold talks about leaving but stressed that he remained part of his plans. There has been no fresh bid from PSG, although they are likely to explore the possibility of agreeing a deal this month. Napoli, Inter Milan and Manchester United are also interested. PSG need and are looking for a playmaker. They would also have the funds to make the sort of offer - in excess of £35 million - that would be seriously considered by Chelsea. Chelsea's players had the day off on Thursday but it is understood that Mata's representatives have attempted to clarify the situation following Mourinho's remarks on Wednesday. Mata made a visible show of his frustration when he was substituted after 53 minutes of the game at Southampton, which Chelsea won 3-0.