In the days leading up to the end of the transfer window we saw a flurry of activity from the biggest clubs in the Premier League, with only Manchester City refraining from completing any last minute deals.

Liverpool and Tottenham were the busiest on deadline day as they significantly strengthened their options with the likes of Mamdou Sakho and Christian Eriksen, but it was Arsenal that grabbed the headlines as they smashed their own transfer record by more than £20m in order to capture Mesut Ozil.

Manchester United were slammed for their lack of activity throughout the window but David Moyes clearly always knew what he was doing as he spent close to £30m on a player that had a release clause of just £23m earlier in the summer.

Traditional big spenders Chelsea flexed their financial muscle by luring Willian away from wanting arms of Tottenham Hotspur, but it was a late deal for Samuel Eto'o that could prove to their be best piece of business.

With the international break out of the way we are set to see debuts for a number of the new arrivals in the Premier League. But just who will make the biggest impact in their first game for their new club?

Instant Impact

There is little doubt that Mesut Ozil is the outstanding player to arrive in England but Marouane Fellaini may well be the man that delivers the biggest impact on his debut. The commanding Belgian is match fit, already knows the league inside and out, and appears tailor made to add an injection of power into a lightweight midfield.

His formidable presence will hand Manchester United a different option in attack, while his ability to disrupt play will add some steel when needed in defence. Fellaini knows exactly what his manager David Moyes will want from him, and you can expect him to dominate the Crystal Palace midfield in what is an important game for United after their toothless display against Liverpool.

Game Changer

There has been plenty written already about the world class talent of Ozil but it is perhaps unlikely that his arrival will spark an immediate impact. Arsenal are coming off the back of an impressive display against north London rivals Tottenham and will be fully expected to travel to the Stadium of Light and pick up a result.

Ozil will undoubtedly display his technical ability but it is perhaps in bigger games that his impact will be felt the most. Often Arsenal were unable to find results in the big games, but with the craft and guile of the technically gifted German they have found the key to unlocking the most resolute of defences. Expect the former Real Madrid man to especially shine in Europe where his eye for a killer pass may just be exactly what Olivier Giroud needs.

Slow Burner

There is little doubt that Christian Eriksen is a player of immense talent. Vision, poise and balance make his a joy to watch but transitioning from the Dutch league where he enjoyed time on the ball, to the often frenetic Premier League may prove a difficult transition. However, his undeniable talent means you can expect him to grow into his role at Tottenham, and eventually he may well prove to be the man that links defence with attack.

Mamdou Sakho is another that may take some time to fully demonstrate his talent but for a different reason. The 23 year old is a powerhouse of a player and has already shown his ability at PSG and for France. It is unlikely he would be intimidated by the physical nature of the Premier League but his main problems lies in the depth of Liverpool's squad. Kolo Toure, Daniel Agger and Martin Skrtel have all excelled already this season and it may take some time for Sakho to force his way in. However, once he does he is sure to be an astute addition for Liverpool.

Judgement Reserved

That leaves us with Chelsea new boy Samuel Eto'o. Far from an unknown quantity but question marks remain as to whether this is the same striker that regular destroyed teams when playing for Barcelona. His stint in Russia was somewhat forgettable but he still scored 25 goals in just 51 league games.

Has he lost his pace? Has the desire gone? We have no idea, yet. Eto'o could struggle at 32 years old but equally he could feast from the incredible service he will receive from the likes of Eden Hazard, Juan Mata, Oscar, Andre Schurrle and Kevin De Bruyne. This one, it seems, is hard to call.