It's much harder to buy good players in the January transfer window.

While clubs are always looking to strengthen, most teams don't want to lose their best players midway through the season.

Moreover, teams that do choose to sell only have a limited time to find a replacement. Of course, that isn't ideal when games are coming thick and fast.

For those reasons, not many big transfers happen in the winter transfer window.

And even if they do, prices are inflated and clubs often overpay in a desperate attempt to get their target.

However, there have been some brilliant signings made in January in the past.

We have ranked the 15 best transfers that Premier League clubs have made in January since 2010.

15. Lucas Moura | Paris Saint-Germain - Spurs | £25m | 2018

Moura has scored 22 times for Spurs since signing in 2018.

His dramatic second-half hat-trick against Ajax, which saw Spurs progress to the 2019 Champions League final, means he was worth every penny.

14. Edin Dzeko | Wolfsburg - Manchester City | £27m | 2011

Dzeko was inspirational as City won their first Premier League title in the 2011/12 season.

The Bosnian striker scored a 91st minute header against QPR on the final day of the campaign, sparking a dramatic late comeback.

That was one of 72 goals Dzeko scored in five seasons with the club.

13. Moussa Sissoko | Toulouse - Newcastle | £1.8m | 2013

Sissoko had been a regular in Ligue 1 for Toulouse for six seasons but Newcastle were still able to snag a bargain when they signed him for just £1.8m in 2011.

The French midfielder would then be a key player for Newcastle in his four seasons at the club as he scored 12 goals in 133 games.

The Magpies made a substantial profit on him when he was sold to Tottenham for £30m in 2016.

12. Daniel Sturridge | Chelsea - Liverpool | £12m | 2013

Sturridge was deadly in front of goal in the early days of his Anfield career.

The striker scored 11 times in 16 games in what was a promising start in his first season.

And he would better that mark the following campaign as he netted 24 times in 33 games.

Injuries would curtail his progress though and he wasn't the same player when he left in 2019.

11. Jermain Defoe | Toronto - Sunderland | Swap | 2015

This deal is made even better given Sunderland gave up Jozy Altidore in exchange, who managed just 1 goal in 42 Premier League games.

Defoe was 32 when he signed but would score a bundle of goals during his stint, which effectively saved Sunderland from relegation.

The English striker managed 19 goals in his first two campaigns with the club. 

Even in 2016/17 when Sunderland were relegated, Defoe managed 15 Premier League goals in 37 games.

10. Abdoulaye Doucouré | Rennes - Watford | £8m | 2016

Doucoure has been a great servant for Watford during his four-year spell at the club.

Signed for just £8m, the Frenchman was named Watford's Player of the Season in 2017/18 and also helped his side to the FA Cup final last year.

A move to a big club beckons.

9. Wilfred Ndidi | KRC Genk - Leicester | £17m | 2017

Ndidi had just turned 21 when Leicester decided to buy him from Genk for £17m.

But that proved to be a great signing as Ndidi has emerged into one of the Premier League's best defensive midfielders.

8. John Stones | Barnsley - Everton | £3m | 2013

Stones didn't feature at all in his first season at Everton.

But he soon established himself as a regular for both club and country and earned a £50m move to Manchester City in 2016.

7. Nemanja Matic | Benfica - Chelsea | £22m | 2014

Chelsea decided to re-sign Matic in 2014 and he would go on to play a key role as the Blues won two Premier League titles.

He made 151 appearances during his second stint at the club before joining Manchester United for £40m in 2017.

6. Gary Cahill | Bolton - Chelsea | £7m | 2012

Cahill would form a solid partnership with John Terry in defence during his time at Chelsea.

He made 290 appearances for the Blues and chipped in with 25 goals before leaving in 2019.

The Englishman helped Chelsea to eight major trophies, including one Champions League triumph and two Premier League titles.

5. Aymeric Laporte | Athletic Bilbao - Man City | £57m | 2018

Laporte was one of the best defenders in La Liga for some time before Man City finally prised him away from Athletic Bilbao in 2018.

They paid a hefty sum for him but he's proven he's up there with Virgil van Dijk as the best centre-back's in the league.

Man City's decline in form while Laporte has been out with injury says a lot about his quality.

4. Philippe Coutinho | Inter Milan - Liverpool | £8.5m | 2013

Liverpool fans have a lot to thank Coutinho for.

The Brazilian midfielder was brilliant during his six season spell, scoring 54 times in 201 appearances.

If he had not forced through a £105m move to Barcelona, Liverpool would arguably never have signed Virgil van Dijk and Alisson Becker.

They lost a brilliant player in 2018 but with the money they got they were able to replace him with two players that were even better. 

3. Pierre-Emerick Aubameyang | Borussia Dortmund - Arsenal | £56m | 2018

Arsenal weren't messing around when they smashed their club-record fee to sign Aubameyang in 2018.

He's scored an impressive 56 goals in 89 games and is now club captain.

2. Luis Suarez | Ajax - Liverpool | £22.8m | 2011

Suarez was a flawed genius.

The Uruguayan was incredible on the pitch but his behaviour often let him down.

Still, he managed 82 goals in 133 games for Liverpool, including scoring 31 Premier League goals in the 2013/14 campaign.

He left in 2014 having established himself as one of the best strikers in the world.

1. Virgil van Dijk | Southampton - Liverpool | £75m | 2018

Many football fans laughed when Liverpool paid £75m for Van Dijk. They aren't laughing any more.

The Dutch defender is now the best defender in the world and has helped Liverpool establish himself as an elite club once again.

Liverpool really are the kings of the January transfer market.

They've done great business midway through the season, with the signings of Sturridge, Coutinho, Suarez and Van Dijk all turning out to be inspired decisions.

Van Dijk isn't just the best signing a Premier League club has made in January since 2010.

He's arguably the best signing a Premier League team has made since the start of last decade, full stop.