Chelsea have completed the signing of Atletico Madrid midfielder Saul Niguez on a season-long loan.
The Blues confirmed the transfer of the Spanish international in the final exchanges of transfer deadline day to bring a mixed last 24 hours of the window to an end for the Champions League holders.
Boss Thomas Tuchel had hoped to be able to work with Sevilla defender Jules Kounde but Chelsea did not meet the release clause of the centre-back.
It meant Saul proved the only incoming player for the west London club on Tuesday with the 26-year-old eager to start this latest chapter in his career.
He said: "I am very excited to start this new challenge with Chelsea. Blues fans, I am one of you now and I can't wait to wear the shirt, start training and see all of you. See you soon!'"
After progressing through the academy at Atletico, the central midfielder went on to help his boyhood club win the LaLiga title, two Europa League trophies and the Copa del Rey having made his debut in 2012.
Chelsea director Marina Granovskaia added: 'We welcome Saul to the club and believe he completes our squad as we compete for honours in five different competitions this season.
"He is a proven winner, a player with huge experience and we know he will be very well-suited to the challenges that face us on all fronts in the coming year."
The Blues were dealt a blow at the start of deadline day when Sevilla's sporting director Monchi laid bare the situation regarding Kounde, who has a £68.7million release clause.
"The only written, formal offer from Chelsea came last Wednesday, around 5pm," said Monchi at a press conference.
"We weren't satisfied with the offer, and it was linked to Chelsea selling a player. It was a decent fee but it didn't meet our criteria. We haven't spoken with Chelsea since Friday night. We all decided that it was best Jules didn't travel to Elche.
"It's normal for players to be affected by news of any kind. Last year he had the interest from (Manchester) City and now Chelsea this year. Kounde's (release) clause never went up to 90million euros. It has always been 80million."
Even though Chelsea were unable to secure the services of the 22-year-old, they did allow Wales international Ethan Ampadu to depart on loan.
He has joined Serie A new boys Venezia on a deal until the end of the season and also signed new terms at Stamford Bridge until the summer of 2024.
Callum Hudson-Odoi did not secure a switch away from the Blues despite being linked with a temporary move to Borussia Dortmund. Tuchel made it clear at the weekend he was unwilling to let the versatile youngster leave.
