Christian Atsu
Christian Atsu impressed while on-loan at Rio Ave in the 2011-12 season. [Reuters]

Chelsea are in advanced talks with Porto winger Christian Atsu as manager Jose Mourinho looks to add yet more depth to his already impressive squad.

The 21 year old broke into the Porto side under Andre Villas-Boas back in 2011 and was subsequently loaned out to Rio Ave where he impressed by scoring six goals in his 27 league appearances.

Atsu continued to excel last season but was linked with an exit after he failed to agree a new contract with the Portuguese champions.

The Ghana international is now in the final year of his contract and was heavily linked with a possible move to Liverpool earlier in the transfer window, before the club sealed a deal for winger Luis Alberto.

Now it appears Chelsea are the favourites to land the winger after Portuguese publication O Jogo reported that Atsu had flown to London to hold talks with Mourinho.

Sky Sports report that Chelsea want to secure his signature before the end of the transfer window and will offer around £3.5m to Porto.

Atsu would have been able to start negotiating with clubs in January over a Bosman deal the following summer but it seems Porto would rather cash-in on the player now than lose him for nothing in 12 months' time.

Chelsea have already significantly strengthened their attacking midfield options with the purchases of Andre Schurrle and Willian but it seems Mourinho is keen to sign an out-and-out winger.

Atsu is normally deployed as a left winger and has become known for being both quick and direct in his style.

The youngster has already been capped 16 times by Ghana and has three goals to his name.