Antoine Griezmann and Saul Niguez were the big names to move late on deadline day, with Atletico Madrid having a busy night.
Griezmann's move to his former club completed a day of outgoings for Barcelona, who sold Emerson Royal and Ilaix Moriba, as well as loaning out Ray Minaj.
Ronald Koeman's Barca did get one player in, however, who will seemingly replace Griezmann in attack.
Barca's LaLiga rivals Real Madrid did not manage to get a mega deal for Kylian Mbappe over the line, despite a reported bid of €200m having been lodged on Tuesday, though Los Blancos did sign Rennes sensation Eduardo Camavinga.
Cristiano Ronaldo's move back to Manchester United was confirmed early on, but there was plenty of late action in England, too.
Another returning king as Chelsea call on Saul
Romelu Lukaku back to Chelsea. Ronaldo back to United. Now, Griezmann has made a return to one of his former clubs, with the 30-year-old re-joining LaLiga champions Atleti on a season-long loan.
There is an option to make the deal permanent for €40million – just the €80million less than Barca paid for the France forward in 2019.
Replacing Griezmann at Barca is Luuk de Jong, with Koeman turning to his compatriot from Sevilla. Messi to De Jong... not quite the end to the window Barca fans would have had in mind.
Saul, meanwhile, is leaving LaLiga. He has joined Chelsea on a loan deal from Atleti, with an option to buy for a reported £30m.
No Madrid move for Mbappe... yet
A third Madrid bid for Mbappe was reportedly lodged, and ignored, on Tuesday, as Florentino Perez's obsessive hunt of the Paris Saint-Germain star proved fruitless.
However, Mbappe is out of contract next year, so he may well be a Galactico soon enough.
One player who will be playing in the famous all-white strip this season is teenage midfielder Camavinga, who has joined from Rennes.
As well as keeping Mbappe, PSG added to their squad, completing a stellar transfer window by signing Sporting CP left-back Nuno Mendes to fill what has proved a problem position. Pablo Sarabia went the other way.
In Italy, Milan marked a quiet end to the window overall by confirming the signings of Yacine Adli and Messias Junior.
Inter already had their business done, while Juventus confirmed Moise Kean's return on Tuesday morning. The Bianconeri also signed Mohamed Ihattaren, who was then loaned to Sampdoria.
Ronaldo headlines Premier League moves
The early confirmation of Ronaldo's move back to United being complete was the biggest story of the day in England's top flight. It also paved the way for the Red Devils to sell Daniel James, who moved to Leeds United.
Arsenal blocked Everton's attempts to sign Ainsley Maitland-Niles, though Hector Bellerin did leave the Gunners to head to Real Betis on loan. Mikel Arteta's Gunners completed their record-breaking transfer window (in terms of overall spend) with the acquisition of Japan defender Takehiro Tomiyasu from Bologna. Earlier in the day, Arsenal loaned out Reiss Nelson and Alex Runarsson.
Their north London rivals Tottenham completed the signing of Emerson from Barca, with Serge Aurier's time at Spurs subsequently being brought to an end by the mutual termination of his contract.
Everton's hunt for a right-back was to no avail. The Toffees did bring in Salomon Rondon on a free transfer, handing the forward a two-year deal with an option for a third. James Rodriguez was involved in a mooted part-exchange deal with Porto for Luis Diaz, but the Colombian star is staying put.
Manchester City rounded off their dealings by sending out seven players on loan. Among them was Patrick Roberts, who was one of three players to join Ligue 1 club Troyes.
Wolves were unable to complete deals for Kieffer Moore or Boubacar Kamara. A late offer from Spurs for Adama Traore was reportedly rejected.
Czech Republic midfielder Alex Kral joined West Ham on loan from Spartak Moscow. He was the Hammers' second signing of the day, with Croatia playmaker Nikola Vlasic having arrived early on.
There were two outgoings at Celtic. Scotland international Ryan Christie signed for Bournemouth, while Crystal Palace bought striker Odsonne Edouard for a reported £15m. The Hoops replaced him with Greece forward Giorgos Giakoumakis.