Liverpool have jolted the transfer market into life by making the first mega-money foray into the January sales with a reported £75million capture of Virgil van Dijk.
A few short months on from failing to land the Dutchman's signature, the Reds have persuaded Van Dijk to join, having parted with a record fee for a defender.
Expensive recruits in defence have become something of a hallmark of this Premier League season, with Manchester City streaking clear at the top after a big-money makeover that focused on defence.
City are well-represented on the list of costly stoppers that Van Dijk now tops, but who else makes the top 10? We took a look.
VIRGIL VAN DIJK - Southampton to Liverpool, £75m
Liverpool were warded off Van Dijk in June after being accused of tapping him up by Southampton, but the defender's absence from several matchday squads meant a departure was never far away.
The Reds gave their fans a late Christmas gift on Wednesday, confirming the 26-year-old will join once the window reopens in January.
Liverpool Football Club can confirm they have reached an agreement with Southampton for the transfer of Virgil van Dijk.Full story: December 27, 2017
BENJAMIN MENDY – Monaco to Manchester City, £51.75m
Pep Guardiola broke the record for a defender when he signed Mendy from Monaco in July, the left-back having quickly established himself as one of Europe's most exciting attacking full-backs in 2016-17 as his side won the Ligue 1 title and reached the Champions League semi-final.
His arrival was part of a spectacular overhaul of the City backline, which has seen them spend close to £165m on three defenders and goalkeeper Ederson, but a serious knee injury curtailed a positive start to life in England for the Frenchman.
DAVID LUIZ – Chelsea to PSG, £50m
Paris Saint-Germain paid a whopping fee to sign Brazil international David Luiz from Chelsea in 2014.
He won the Ligue 1 title in both of his seasons at PSG and he made it three league championships in a row after he returned to Chelsea for £34m in a surprise move in August 2016, claiming his first Premier League winners' medal.
KYLE WALKER – Tottenham to Manchester City, £50m
When Walker joined Spurs from hometown club Sheffield United for £5m in 2009, few would have guessed he would one day become the most expensive English player ever.
Walker is yet to win major silverware in his career, but that looks set to change, with City enjoying a record-breaking winning run in the Premier League.
JOHN STONES – Everton to Manchester City, £47.5m
City have shown a willingness to pay massive amounts for English talent, with Stones having joined the club from Everton last year.
The 23-year-old had a difficult first campaign as Guardiola's side under-performed, but his performances have mirrored the team's this season, although he too has succumbed to injury.
DAVINSON SANCHEZ – Ajax to Tottenham, £36.6m
Spurs waited weeks to make their first signing of the transfer window, but did so in some style, smashing their club record to bring Sanchez to north London.
The former Atletico Nacional man reportedly caught Barcelona's attention during Ajax's run to the Europa League final last year and he has made a solid, if unspectacular, start to life in the Premier League.
LEONARDO BONUCCI – Juventus to AC Milan, £35.2m
A row with Juve head coach Massimiliano Allegri saw Bonucci be allowed to join Serie A rivals AC Milan, who splashed the cash in a bid to return to the Champions League.
Bonucci has won six Serie A titles at Juventus, but he twice lost in the Champions League final. Such success won't be following at San Siro any time soon, with Bonucci's form nose-diving amid Milan's struggles under Vincenzo Montella and Gennaro Gattuso.
SHKODRAN MUSTAFI – Valencia to Arsenal, £35m
Arsenal are not normally known for their big spending, with Arsene Wenger one of world football's more parsimonious managers, but they forked out £35m to sign Mustafi from Valencia in August 2016.
The Germany international had a solid first campaign at the Emirates Stadium, but the Gunners missed out on Champions League qualification for the first time since 1997.
ANTONIO RUDIGER – Roma to Chelsea, £34m
With club icon John Terry having left Stamford Bridge, Chelsea were in need of a new defensive lynchpin and they turned to Mustafi's international colleague Rudiger, who joined from Roma.
The 24-year arrived in London fresh from Germany's success at the Confederations Cup and has slotted into Antonio Conte's plans neatly.
THIAGO SILVA – Milan to PSG, £33m
PSG's second entry is their club captain, Thiago Silva, with the Brazilian having been a major success since joining in 2012.
Although PSG were unceremoniously overhauled by Monaco to end their dominance of Ligue 1 last season, the 32-year-old has won four league titles and three Coupes de France in Paris.
And with normal service restored this season, expect that list of honours to grow.
(*Prices are as reported at the time of transfers being completed.)
