Alejandro Garnacho told Manchester United "we're the best team in the world" after joining Chelsea from Ruben Amorim's struggling side. United finished 15th in the Premier League last season and only beat relegation battlers Burnley 3-2 yesterday thanks to a 97th-minute Bruno Fernandes penalty.
Days earlier, United crashed out of the Carabao Cup in the second round to League Two Grimsby Town on penalties. That leaves the FA Cup as the only plausible trophy United can win this season, despite the fact it is still only August. But Garnacho will not be a part of the Red Devils' cause having swapped United for Chelsea in a £40million move on Saturday.
The Argentina international, 21, has joined on a seven-year contract and will compete with Jamie Gittens for a starting spot on the left wing. Garnacho, whose fee represents United's fourth-largest sale ever, can also play on the right and is seen as a real coup for the Blues.
He was at Stamford Bridge to watch Chelsea beat Fulham 2-0 and then reminded former employers United of the London club's recent success: "It's an incredible moment for my family and I to join this great club. I can't wait to get started. I watched the Club World Cup and to join the world champions is special – we're the best team in the world!"
Garnacho has been warned by another former Chelsea attacker, Joe Cole, that he needs to work hard after falling out with Ruben Amorim at Old Trafford. Cole said on TNT Sports: "At his best is the crucial thing because he's going to be competing with Gittens you would imagine for that left wing role and coming in on his right foot.
"He has moments where he looks sensational and looks outstanding. We see Manchester United probably isn't a great environment for a young player at the moment. We've seen players like [Scott] McTominay leave and thrive.
"There's levels to go up for Garnacho. I think it's a good price for Chelsea. There's question marks on the lad, I don't know him but the ins and outs and the things that come out from his camp and how he’s handled being dropped at Manchester United I think that needs to improve.
"If he wants to knuckle down and become a top player that he can become, he needs to come to a good environment which I think Chelsea is and grow from there. But there's lots of competition for those wide positions."
Chelsea have meanwhile pulled out of a deal to send Nicolas Jackson on loan to Bayern Munich for the season. The striker is expected to return to London in the coming days because of summer signing Liam Delap's injury which is set to rule him out for eight weeks or more.