The transfer window is beginning to hot up and a number of big teams have completed deals this week. 

Manchester United shocked everyone when they made a bid reported to be around £75 million for Everton's Romelu Lukaku. 

It was thought that the Belgian striker was top of Chelsea's summer wishlist, but Jose Mourinho blindsided his old team to secure the 24-year-olds signature.

He officially joined the Red Devils this week and has already begun training with them. 

After missing out on Lukaku, the Blues wasted little time reaching a deal with AS Monaco for another of their targets. 

Tiemoue Bakayoko is set to move to Stamford Bridge in a £40 million transfer, subject to passing his medical. 

Across London, Arsenal secured their first major summer signing, landing Alexandre Lacazette from Lyon. He has already scored for the Gunners during his first pre-season appearance.  

It's believed that the Frenchman will not be the only player to come into Arsenal this summer. The team struggled last season, finishing fifth in the Premier League.

To challenge the top four again, Arsene Wenger needs some fresh faces at the Emirates.  

Kylian Mbappe was rumoured to be on Arsenal's radar, but with a £100 million price tag and Real Madrid circling, a deal for him may not be achievable.  

According to a number of reports, Wenger is targeting Leicester City's Riyad Mahrez to add to his attacking options instead.

The Algerian was named the PFA Player of the Year in 2016 after leading his side to the league title, but had a disappointing season following that.

Still, he's expected to leave the Foxes for a bigger club this summer. But with Arsenal deterred by Leicester's valuation of £50 million, he may not move to a rival.

Instead, he could be on his way to Italy. According to the Daily Mail, AS Roma have made a £29 million bid for Mahrez.    

Of course, that's still way off the English clubs asking price. However, as the winger has already handed in a transfer request, they may be forced to sell him for less than £50 million. 

And they would much rather let him move to a club they won't be competing with next season, rather than seeing him playing in the Premier League for a team like Arsenal.