We've reached the first transfer window of the new decade and January will no doubt be dominated by rumours of big-money moves. 

Europe's top teams will all be linked with signing some of the best players in the world. But if any exciting transfers do happen, we should be wary that not all of them pay off.

In fact, over the last 10 years, we've seen some real shockers. 

With the decade now done, here at GIVEMESPORT we've decided to rank 10 of the worst transfers in world football between 2010 and 2020. 

Check out the list below.

10) Paco Alcacer | Valencia to Barcelona (2016) | £25.58m

Alcacer arrived at the Camp Nou after scoring over 10 goals in his two previous La Liga campaigns. 

But he was Barcelona's fourth-choice attacker behind Lionel Messi, Neymar and Luis Suarez and never established himself, making just 15 league starts.

The Spaniard has since gone on to star for Borussia Dortmund and his national team since leaving.

9) Memphis Depay | PSV to Manchester United (2015) | £31m 

Manchester United signed Depay in 2015 after he netted 22 goals for PSV and finished as the Eredivisie top scorer. 

But in his first season, the Dutchman managed just two goals in 29 Premier League appearances - failing to adjust to English football. 

Depay was sold 18 months after arriving at Old Trafford and like Alcacer, has since gone on to impress for his new team Lyon, as well as Holland.  

8) Thomas Lemar | Monaco to Atletico Madrid (2018) | £51m

After two impressive Ligue 1 campaigns with Monaco, Lemar lifted the World Cup with France in 2018 and earned a move to Atletico Madrid. 

But the winger managed just three goals in 31 La Liga matches in his debut season - and he's currently goalless in 15 games so far in 2019/20. 

With Antoine Griezmann no longer in Madrid, it was hoped Lemar could fill the hole he left, but that looks unlikely. 

7) Neymar | Barcelona to PSG (2017) | £189m

Now, this transfer makes the list for a different reason to all the rest. Neymar has been impressive since joining PSG - scoring 60 goals in 70 appearances while winning back-to-back titles. 

But it's his injuries and off-field antics that put the Brazilian on this list. He's missed a ridiculous 58 games through injury and has served bans for abusing referees and getting into altercations with fans. 

Of course, there's also the constant talk he'll rejoin Barcelona in the near future. A complete waste of money? No. But was Neymar really worth £189m? Probably not. 

6) Bebe | Vitoria to Manchester United (2010) | £7.4m

"On this occasion, I didn’t watch him." Those were Sir Alex Ferguson's words after Man United signed Bebe 10 years ago. 

"It's the first time I have done it. Normally I see plenty of video footage but our scouting department is very good and sometimes you have to go on instinct."

Well, instinct was wrong on this one. United moved for Bebe after reports that Europe's top clubs, including Real Madrid, wanted to sign him. 

But after his first season at Old Trafford, it was clear the teenager needed a lot more development and he was sent on loan for the next three years. 

Bebe never established himself after that and was sold to Benfica without making any more appearances for United. What a terrible transfer that was. 

5) Danny Drinkwater | Leicester City to Chelsea (2017) | £35m 

Drinkwater joined N'Golo Kante, his former Leicester midfield partner, 12 months after the Frenchman arrived at Chelsea. 

While Kante has gone on to establish himself as one of the best players in Europe, Drinkwater's career has gone the opposite direction. 

He struggled to break into Chelsea's first-team and was sent on loan to Burnley, where he's made just one appearance after suffering a serious injury on a night out. 

4) Leonardo Bonucci | Juventus to AC Milan (2017) | £35m

After winning six consecutive Serie A titles at Juventus, Bonucci moved to AC Milan for a new challenge, hoping to restore the club to former glories. 

But that's not how it worked out. After being named captain and signing a five-year deal, the Italian could only help the Rossoneri to a sixth-placed finish. 

He jumped ship back to Juve after one season and has since won another title.  

3) Angel Di Maria | Real Madrid to Manchester United (2014) | £59.7m

Di Maria's big-money move to Man United had fans seriously excited six years ago. But after a solid start, he was used sparingly as a substitute by Louis van Gaal come the end of his first season. 

After just 12 months at Old Trafford, the club cut their losses and sold Di Maria on to PSG for less than £44m. He's become a solid forward for the French club since. 

2) Philippe Coutinho | Liverpool to Barcelona (2018) | £102 million

Barcelona expected Coutinho to slot in seamlessly alongside Messi and Suarez in their front line. But that didn't happen, as the Brazilian struggled to adapt to life in Spain. 

In one and a half seasons, he netted 21 goals in 76 appearances and has since been loaned out to Bayern Munich and replaced by Griezmann. 

Liverpool, on the other hand, are European champions and should win the Premier League without their former star player. 

1) Alexis Sanchez | Arsenal to Manchester United (2018) | Swap deal

Perhaps the worst swap deal - and transfer - in Premier League history. Nearly £500,000-a-week in wages at Old Trafford and just five goals in 45 appearances. 

Sanchez's arrival seriously upset the balance at United and led to the likes of David de Gea and Marcus Rashford stall on their contracts. 

Now though, he's off the books and on-loan at Inter Milan, where he's picked up another injury. Is the Chilean's time at the top done? Most probably. 

There we have it, the 10 transfers GIVEMESPORT have ranked as the worst of the last decade. 

Of course, there are notable omissions in Andy Carroll, Wilfried Bony and Roberto Soldado, amongst a few others. 

But there's no denying that Sanchez deserves to be placed at the top of the list. He was by far the worst signing of the decade and in fact, one of the worst of all-time. 

Hopefully, the next 10 years will bless us with more shockingly good - rather than shockingly bad - deals.