The 22-year-old right-back boasts prior experience in the Premier League, having made ten appearances in the top flight whilst on loan at Liverpool during the 2014/15 season.
Right-back has emerged as a real problem area for the Black Cats since the start of last season. Loan signing DeAndre Yedlin took the role from Billy Jones in the second half of 2015/16, but the USA international joined Newcastle United for an undisclosed fee earlier this week.
Summer signing Donald Love has started there during Sunderland’s first two Premier League fixtures of the current campaign, but Manquillo’s arrival suggests David Moyes isn’t fully convinced by the former Manchester United youngster.
Manquillo was part of the Atletico Madrid squad that lifted the La Liga title in 2013/14, making three appearances in the Spanish top flight, but spent last season on loan at Marseille.
Here’s how he compared to Sunderland’s full-back options from last term during his spell with the French club (courtesy of Squawka):
Manquillo has joined Sunderland on a season-long loan to become David Moyes’ fifth summer signing, but it comes with the option of the Spaniard moving to the Stadium of Light permanently once the loan deal expires.
Here’s a look at the Atletico hotshot in action: