Victor Valdes has told Sky Sports that he felt lonely at Manchester United but does not hold a grudge against former manager Louis van Gaal.
Former Barcelona goalkeeper Valdes had a fall-out with Van Gaal while the pair were at United and he was frozen out of the first-team squad then sent out on loan to Standard Liege.
The 34-year-old is back in the Premier League this season, playing for Middlesbrough, and does not have bad feelings about his sour ending at United.
Valdes said: "I feel like a professional footballer again after all those hard days in Manchester.
"It's difficult to explain, but it was hard being alone. Sometimes at United, I thought 'I don't need this,' but I am a fighter and a professional.
"This was the biggest fight of my career and I won it. The easy way out was to end my career but now I feel like a professional goalkeeper again. I don't have any bad words for Van Gaal or Manchester United."
Valdes remembers the better times he had with the Dutchman, who was Barcelona head coach when the goalkeeper was rising up through the ranks as a teenager. Van Gaal also signed Valdes for United in January 2015 and supported him despite a knee problem.
The Middlesbrough goalkeeper said: "They helped me through my injury and the manager gave me my chance as a footballer at Barcelona and then again at United.
"He's like a father figure to me. I don't want to remember the last six months in a bad way. For me, he is in the top. We are still friends and there is no problem between us.
"I want to say, in a public way, thank you to the U21 coach Alan Fettis. Without him, I may have given up football. He made me keep going and stopped me when I was thinking about bringing my career to an end."