Who has been Spanish football's best January signing in the past 15 years? Transfer Market Marcelo, Costa and Rakitic are candidates

Many clubs often cite the January transfer market as one where it's difficult for them to complete deals, but there have been some success stories over the years.

Yet just which one is the best winter signing made in LaLiga Santander over the past 15 years?

Here, we look at the best one from each of the past years.

2005/06: Cicinho (Real Madrid)

The Brazilian defender arrived to bolster Los Blancos' Brazilian contingent and quickly settled into life at the club.

He played regularly in the second half of the season, but a knee injury in 2006/07 would seriously hinder his progress.

He would eventually leave Real Madrid with a LaLiga winners medal.

2006/07: Marcelo (Real Madrid)

Los Merengues once again looked to Brazil to improve their defence and Marcelo arrived from Fluminense as one of the potential stars of the future.

The club signed him alongside Fernando Gago and Gonzalo Higuain in the hope of putting in place a team for the future, but Marcelo was undoubtedly the best.

He has gone on to become one of the greatest ever foreign players to ever represent Real Madrid, and is still there to this day after having won four Champions Leagues.

2007/08: Ever Banega (Valencia)

The Argentine struggled to perform in the second half of the season after his arrival, but he would go onto become a player of immense class in the Spanish top flight.

His form would earn him a move to Atletico Madrid.

2008/09: Lassana Diarra (Real Madrid)

The French midfielder arrived at a difficult time in Real Madrid, with Pep Guardiola's Barcelona powering towards dominance, however the midfielder added something to the team.

He would eventually be a reliable presence upon Jose Mourinho's arrival, winning a Copa del Rey and LaLiga title.

2009/10: Dani Osvaldo (Espanyol)

After arriving in January 2010, the powerful centre-forward scored seven goals before the end of the campaign, while he would improve in the next campaign as he found the net 13 times before Roma signed him.

2010/11: Ivan Rakitic (Sevilla)

Monchi vastly improved the Sevilla midfield in January 2011 by signing both Gary Medel and Ivan Rakitic.

Los Rojiblancos paid just 1.5 million euros for the Croatian and he would end up moving to Barcelona for 21m euros in total, after having helped the club to Europa League glory.

2011/12: Diego Costa (Rayo Vallecano)

Diego Costa first emerged with Rayo Vallecano, and he scored 10 goals in the months after his transfer was completed.

He formed a partnership with Michu that supporters will never forget, and it earned both players moves to greener pastures.

2012/13: Nolito (Granada)

Before finding his best form with Celta Vigo, the Spanish winger spent half a season with Granada where he was excellent.

He scored three goals in 17 matches and was crucial to the club avoiding relegation.

2013/14: Nordin Amrabat (Malaga)

The Moroccan had an immediate impact on Malaga, where he played as a starter in 15 LaLiga Santander matches, scoring two goals.

2014/15: Fernando Torres (Atletico Madrid)

Arguably the most anticipated homecoming in Spanish football's modern history, Fernando Torres returned to Atletico Madrid as a hero in desperate need of help.

A dismal loan spell with AC Milan compounded on his woes from a mixed Chelsea career, yet he filled the Estadio Vicente Calderon upon his return.

He would go on to become a vital rotation option for Diego Simeone and he would play in a Champions League final and win the Europa League before leaving again.

2015/16: Giuseppe Rossi (Levante)

Six goals in the final months of the season made Levante think they had signed a player who could star for them, but injuries continued to blight his progress.

2016/17: Clement Lenglet (Sevilla)

Another player on the Monchi assembly line, the French defender arrived from Nancy and was immediately parachuted into the starting XI in Seville.

He is now a starting defender for Barcelona and has won a LaLiga Santander title.

2017/18: Ingo Martinez (Athletic Club)

With Athletic Club desperately needing to replace the departing Aymeric Laporte in January 2018, the Basque club signed the Spanish defender from Real Sociedad, where fans have still not forgiven him.

His form has been excellent since, and he has outshone Philippe Coutinho who also arrived in Spain during the same month.

2018/19: Alvaro Morata (Atletico Madrid)

A long-time wish of Simeone, Morata arrived from Chelsea and immediately adapted by scoring six goals in his first half season with Los Colchoneros.

He is the starting No.9 for the club now and could lead the line for Spain at Euro 2020.

2019/20: En-Nesyri, De Tomas, Alena... Cavani?

It's necessary to wait to see how these respective transfers play out for the remainder of the 2019/20 season, but for the moment the signing of Youssef En-Nesyri stands out for Sevilla.

However, Edinson Cavani signing for Atletico Madrid would leave such a signing in the shadows.