The Argentine had been frozen out at Old Trafford under previous manager Ruben Amorim, who had banished the winger to his ‘bomb squad’, alongside the likes of Marcus Rashford, Jadon Sancho, Antony and Tyrell Malacia, all of whom trained away from the first-team fold after being told to find moves elsewhere.
He has underwhelmed since his arrival in the capital, however, struggling to nail down a starting berth under either Enzo Maresca or new boss Liam Rosenior.
"I remember in the last six months I was just not playing like before at Manchester United,” he said.
“I started to be on the bench, it's not [such a] bad thing, I was only 20 years old, but in my mind it was like I had to play every game.
“In my mind, maybe it is also on me, I started to do some bad things. But yes, it was just this moment in life and sometimes you have to make decisions and I am really proud to be here and still in the Premier League at a club like this.
“Everyone knows the team we have and the things we can do. Sometimes, we have better moments or worse moments. I am proud to be here but with United, I have nothing wrong to say about the club, no one in the club or the teammates.
He announced himself on the big stage with goals against Real Sociedad and Fulham in late 2022, before establishing himself as a regular first-team fixture the following campaign.
However, after a dressing room fall-out with ten Hag’s successor Amorim, Garnacho went on to pastures new in a move that he admits hurt.
“They gave me the confidence from the start, from Spain, to bring me to the academy, then they brought me to the first team, so it was like four or five years, and amazing love from everyone, from the fans, the stadium, everything was really good.
“It's just sometimes you have to change for the good of your life or the next steps. I only have good memories of Man United.”
Garnacho has played 33 games in all competitions for Chelsea this term, scoring six times. Four of those strikes have come in the EFL Cup, and one has come in the Premier League.