It's been a huge transfer window this summer, with the world's biggest superstars switching clubs and sending football lovers into total meltdown. In fact, it looks like a fantasy come true as many still find it difficult to believe what has happened.Lionel Messi's switch to Paris Saint-Germain and Cristiano Ronaldo's Manchester United return have headlined the transfer window so far but the likes of Romelu Lukaku, Jadon Sancho, Jack Grealish and Raphael Varane have also enjoyed a fair share of attention following their respective transfers.The transfer window will slam shut very soon. Yet, European heavyweights are still working tirelessly to strengthen certain areas of their squad before it's finally over. That means we can still witness a couple of major transfers on deadline day.With just over 24 hours left, we we've come up with a prediction of five major transfers that could happen before the deadline. They are as follows.#5 Ilaix Moriba | Barcelona to RB LeipzigRB Leipzig have decided to pay Barcelona's asking price for the midfielderBarcelona have put Ilaix Moriba up for sale after failing to reach an agreement with the young midfielder over a new contract due to his wage demands. Bundesliga outfit RB Leipzig have shown interest in signing the player and it looks like he could make a last-gasp switch to the Red Bull Arena before the transfer window shuts.Huge deal for RB Leipzig! Ilaix Moriba is a done deal ✅He will undergo his medical check tomorrow in Leipzig and sign a 5 year contract until 2026.RB will pay under 20m€ for Ilaix. Big signing for them and the Bundesliga#TransferUpdate pic.twitter.com/L7xfn8MyPZ— Max Bielefeld (@Sky_MaxB) August 30, 2021According to reports, the German outfit have agreed to pay Barca's €20 million asking price plus several bonuses and Moriba will likely sign a five-year deal at the club. An announcement is expected to be made in the coming hours.#4 Houssem Aouar | Lyon to ArsenalThe midfielder has been offered to ArsenalArsenal have been linked with Olympique Lyonnais midfielder Houssem Aouar throughout the summer - with Mikel Arteta looking to shake things up in midfield - and it seems they could finally reach a breakthrough as the transfer window approaches its end.As per many sources, the Ligue 1 giants are desperate to sell the player and have offered him, initially on a loan deal, to Arsenal and Tottenham Hotspur. The Londoners are now working on the final details in a bid to pip their local rivals to the Frenchman's signature.Lyon have offered Houssem Aouar to Arsenal, but the Gunners have not responded yet, according to @FabrizioRomano. [via @afc24news] #afc pic.twitter.com/EVP4G4Tmld— DailyAFC (@DailyAFC) August 26, 2021Arteta is reportedly looking forward to having Houssem Aouar in his side due to his contributions in the offensive third. The midfielder endured a frustrating spell by his standards with Lyon last season, bagging two goals and four assists in 33 appearances for the French giants.