A busy deadline day did not disguise a quiet transfer window for Premier League clubs, with net spending in the English top-flight down nearly 50 percent compared to 12 months ago.

AFP Sport looks at the key questions surrounding five of the Premier League's top clubs after the window slammed shut on Friday evening:

Is there method to Chelsea madness?

Chelsea have been the exception to a rare summer of Premier League fiscal responsibility as the Blues added to an already bloated squad with a flurry of new arrivals.

The number of players on Chelsea's books has soared above 50 with 11 new signings.

Portugal internationals Pedro Neto and Joao Felix were joined at Stamford Bridge by Jadon Sancho, who made a deadline day move from Manchester United on loan.

But the west Londoners have again largely focused on recruiting young talent from around the globe on long contracts.

To comply with financial sustainability rules, a number of Chelsea's academy graduates have had to be sold, including England midfielder Conor Gallagher, much to the displeasure of supporters.

Chelsea's American owners believe they are playing the long game with a host of assets that will either grow in value to resell in the market or help turn the club into contenders at the top of the Premier League.

A 2-0 opening weekend defeat to Manchester City was a lesson in how far they have to go, but a 6-2 thrashing of Wolves showed some of the potential Chelsea have scooped up over recent years as Noni Madueke and Cole Palmer shone.

Liverpool clever or too cautious?

During a close-season of change at Anfield, the one thing practically untouched is Liverpool's squad.

Arne Slot has succeeded Jurgen Klopp as manager while Richard Hughes has been appointed sporting director and Michael Edwards has returned as chief executive of football.

Liverpool did not make a single signing until the closing days of the window when Federico Chiesa joined in a cut-price deal from Juventus, while goalkeeper Giorgi Mamardashvili will arrive from Valencia in 2025.

Signing the pair for around £35 million ($46 million) represents remarkable value, but the Reds stand accused of not being bold enough to challenge Manchester City and Arsenal for the title.

Have Arsenal done enough?

Arsenal pounced on the chaos at Chelsea to bolster their attacking options at the last minute with a loan deal for Raheem Sterling.

The Gunners also strengthened what was already the best defence in the league last season with Italian international Riccardo Calafiori and added Spain midfielder Mikel Merino.

Arsenal amassed 89 points last season but still missed out on a first title for 20 years to City.

Should Mikel Arteta's men fail to get over the line once more, there will be questions asked about their refusal to go after a proven number nine.

Kai Havertz has come good as a centre-forward after a slow start to his Arsenal career, but the German international's best ever scoring season in the Premier League amounted to just 13 goals.

Man Utd's defensive rebuild

United's new sporting structure off the field got to work with five major signings in a £200 million spree.

Other than Dutch forward Joshua Zirkzee, the rest of the  recruiting was focused on making United harder to beat than when they finished eighth last season.

Centre-backs Leny Yoro and Matthijs de Ligt and right-back Noussair Mazraoui bolstered the backline and will have extra protection in front of them from Uruguayan midfielder Manuel Ugarte, who joined from Paris Saint-Germain on Friday.

United's defending was again far from convincing in a 2-1 defeat to Brighton last weekend and the pressure is on Erik ten Hag to deliver results now he has been backed by his bosses.

Are Man City being complacent?

Pep Guardiola admitted he is running a risk after not replacing Julian Alvarez despite making a massive profit on the Argentine's move to Atletico Madrid.

Erling Haaland is the only natural number nine left in City's squad and the champions can ill afford to lose the Norwegian for any length of time to injury.