Diego Simeone was tasked with his biggest rebuild since taking charge in 2011 after an exodus that not only drained his team of talent, including star man Antoine Griezmann, but caused many to wonder if the team could ever be the same again.
They lost four defenders, with full-backs Filipe Luis and Juanfran going to Brazil with Flamengo and Sao Paulo, captain Diego Godin moving to Inter Milan, and young gem Lucas Hernandez snapped up by Bayern Munich.
They also lost their defensive midfielder Rodri to Manchester City after just a year at the club, while the spat between Atleti and Barca over Griezmann's messy departure left a bad taste in the mouth.
Few would expect Griezmann and the €75 million ($84 million) Frenkie de Jong not to make Barca even stronger, an ominous prospect given they won La Liga by 11 points only three months ago, but Atletico look best-placed to capitalise should they falter.
Forward Felix is at the heart of the optimism following his arrival for €120 million, erasing the pain of the Frenchman's exit even before a competitive ball has been kicked.
The 19-year-old has dazzled during pre-season, his most impressive outing coming against Juventus and his fellow Portugese Cristiano Ronaldo on Saturday, when he scored one and set up the other in a 2-1 win in Stockholm.
"Wherever you put him, he reads the game really well," said Simeone. "The best thing about him though is that he wants to learn. When this is the case, adaptation is always quicker."
Mario Hermoso, Kieran Trippier and Renan Lodi all appear excellent defensive additions while Marcos Llorente from Real Madrid should prove a shrewd replacement for silky Rodri.
Atletico finished 12 points ahead of Real last season and a series of bad summer displays from Zinedine Zidane's side — including a 7-3 defeat to their Madrid rivals — inspire little confidence despite the arrival of Eden Hazard.
Zidane was frustrated in his bid to bring in Paul Pogba, while sidelined players Gareth Bale and James Rodriguez remain in the squad.
"We have the squad we have," Zidane said last week.
"Anything can happen in the last three weeks of the transfer window but we want to have a great season and we have to be ready to play on Saturday, nothing else."
Real reject Julen Lopetegui will be hoping for more patience at Sevilla, where a frantic transfer window has seen 12 players arrive, including Dutch international striker Luuk de Jong, and 11 depart.
De Jong will be tasked with filling the void left by Pablo Sarabia, who left for Paris Saint-Germain, and Wissam Ben Yedder, who has joined Monaco.
Challenging Sevilla for the top four will be Valencia, who have endured a similarly chaotic summer amid tensions between Singaporean owner Peter Lim and the general manager Mateu Alemany,Read More