David de Gea believes he is now in the best form of his Manchester United career but admits there were times during his troubled start at Old Trafford when he considered returning to Spain.
The goalkeeper was praised by manager Louis van Gaal after his outstanding performance against Everton on Sunday, when he saved a Leighton Baines penalty in a 2-1 win.
And he has become an automatic choice for United, helping them win the Premier League title in 2012-13, when he was voted a member of the PFA team of the season, and being named the club's player of the year for his efforts in the 2013-14 campaign.
But De Gea, who was a 20 million-euro signing from Atletico Madrid in 2011, endured mixed fortunes initially and was dropped in favour of Anders Lindegaard during both his first and second seasons at Old Trafford.
He feels the experience made him a finer goalkeeper but conceded he thought of going back to his homeland.
"Sometimes," he said. "I was difficult when you get a lot of criticism like I did. But I kept strong and I always tried to remain positive. I loved training. It was a great pleasure so I just did my work and worked through it.
"Those early days were difficult for me and my family. But when you play for a big club like Manchester United it is normal when you don't play well. I am glad it happened in some ways because the criticism makes you stronger.
"I think I am playing the best football of my career. I have been here for three years and in the beginning it was difficult. Now I am ready for everything.
"I think that experience at the start at United has helped me be the player and man I am now. When you have bad moments you have to improve. You have to become stronger to deal with it, and I believe I have become stronger. I am a much better goalkeeper now."
De Gea said he was applauded by his Everton counterpart for his performance on Sunday but modestly insisted he was not the match-winner.
"Tim Howard came up to me after the game and said I had played a fantastic game," he added.
"I didn't win the match. It was the team who won the match. We scored and defended well. It was about the team and not just me."
Baines had boasted a 100 percent record from the penalty spot in the Premier League after converting 14 spot kicks from as many attempts before De Gea parried his first-half effort, much to the relief of left-back Luke Shaw, who had brought down Tony Hibbert.
De Gea explained: "I had watched Everton penalties before the game and I decided to go to my right and I got lucky. I heard it was the first one he has missed. So I am happy about that. Luke was very pleased -- he thanked me."