Chelsea agreed a late, record-breaking deal to sign Enzo Fernandez from Benfica for £107million as transfer deadline finished dramatically on Tuesday night.
It turned out to be a busy, late, deadline day with deals being confirmed right up until the 23:00 cut-off and some soon afterwards, including midfielder Marcel Sabitzer joining Manchester United on loan from Bayern Munich, Jorginho swapping Chelsea for Arsenal in a £12m deal and Pedro Porro making the switch from Sporting Lisbon to Tottenham, initially on loan until the end of the season.
More than £275m was lavished on deadline day alone - a large part of it by Chelsea - before the window closed, with other deals announced like Southampton completing a club record £22m move for Ghana winger Kamaldeen Sulemana.
Saints, who are bottom of the Premier League, also secured the services of 28-year-old striker Paul Onuachu from Genk for an undisclosed fee on a deal until 2026.
Boss Nathan Jones will hope their new arrivals will spark a run for safety with the south coast club 6/5 Not To Be Relegated and 8/13 to go down this term.
Bournemouth brought in Ukraine centre-back Illia Zabarnyi for a reported £24m, and Ivory Coast midfielder Hamed Traore on an initial loan before a possible £20m summer move, while centre-back Harry Souttar joined Leicester from Stoke City in a transfer which could rise to £20m, and Crystal Palace landed Stuttgart youngster Naouirou Ahamada for £9.7m.
Earlier in the day, Joao Cancelo's surprise loan move from Manchester City to Bayern Munich went through, Leeds signed teenage defender Diogo Monteiro from Servette and Newcastle snapped up West Ham youngster Harrison Ashby for £3m.
The major moves of the day involved Chelsea, though, as the Londoners' staggering spending spree in January continued right up until the last minutes of the month.
The highlight was their eye-watering £107m capture of Argentinian midfielder Fernandez, a move - when it is officially confirmed - that will eclipse Man City's previous record-breaking £100m signing of Jack Grealish from Aston Villa.
The Blues somehow spent an astonishing £288m in the winter window, with Fernandez joining the earlier captures of £88.5m Mykhailo Mudryk, Malo Gusto (£30.7m), Benoit Badiashile (£35m), Noni Madueke (£30.7m), Andrey Santos (£18m) and David Datro Fofana (£8m-£10m).
They also brought in Portugal forward Joao Felix on loan from Atletico Madrid at a cost of around £10m and it moves the total outlay at Stamford Bridge since new American owner Todd Boehly bought them last year up to about a mammoth £580m on 17 new players.
Boss Graham Potter now has several expensive players to try and integrate into his squad as the former Brighton manager attempts to get Chelsea back in contention for a top-four place in the second half of the campaign.
Spending huge amounts may appease some fans but it will be a big task now for Potter trying to put the puzzle together.
The Blues, who are 10th in the table, currently 10 points off fourth place, are 15/2 to Finish In Top 4, while Potter's men are 1/12 to miss out on the Champions League places.
Arsenal will be pleased to secure the services of defensive midfielder Jorginho for just £12m as their London rivals needed to offload some players to make room for the new arrivals.
The Italian will add much-needed cover in the Gunners midfield and help bolster their title challenge.
Mikel Arteta's side are 8/11 to win the Premier League Outright, ahead of City at 5/4 and Manchester United at 40/1.
United reacted to the news Christian Eriksen is facing several months out injured by bringing in Sabitzer on loan from Bayern. The 28-year-old Austria international, who has 68 caps for his country, will add experience and steel to the Red Devils' midfield.
Tottenham, meanwhile, finally landed Porro after a lengthy pursuit and was a deal that had looked off at one point on Tuesday.
The full-back eventually made the move to the Tottenham Hotspur Stadium after Matt Doherty made a shock switch to Spanish side Atletico Madrid.
Spain international Porro joins on loan to begin with but Spurs have an obligation to buy for £40m in the summer.
Spurs are 11/4 to Finish In Top 4 this season following their January business.
Nottingham Forest were also busy on deadline day, signing Atletico Madrid's Brazilian defender Felipe and Newcastle midfielder Jonjo Shelvey for undisclosed fees, while experienced Paris Saint-Germain goalkeeper Keylor Navas arrived at the City Ground on loan.
Some of the more minor deals announced on deadline day included Fulham's capture of Serbia midfielder Sasa Lukic from Torino for an undisclosed fee, while Leicester landed forward Nathan Opoku from FDM Field Masters Sporting Club, also for an undisclosed fee, before sending him out on loan to Belgian side OH Leuven for the rest of the season.
Spare a thought, though, for Everton and new boss Sean Dyche who, despite chasing several targets on deadline day, including Chelsea's Conor Gallagher, were unable to add to their ranks to boost their relegation scrap between now and May.
The Toffees, who are in the bottom three, are 8/13 in the To Be Relegated market, while Forest, following their ongoing recruitment drive, are 5/2 to go down.