Iniesta, who scored the extra-time winner for Spain in the FIFA World Cup Final against Holland on Sunday, struggled for long periods last season with a thigh problem and only reappeared for Barcelona right at the end of the campaign. The midfielder then aggravated the injury in Spain's friendly win over Poland before the start of the FIFA World Cup and was forced off once more as Del Bosque's side went down 1-0 to Switzerland in their opening match in South Africa.
But the 26 year-old returned to play a key part in Spain's first ever FIFA World Cup success and scored the crucial goal four minutes from the end of extra time on Sunday.
"I have always had faith and confidence. I had a lot of confidence in this team from the very first moment." he said in a press conference organised by Nike in Barcelona on Tuesday.
"It has been a difficult season, hard for me in many ways, but there have also been moments of the season when I have felt good. It has simply been a hard season and nothing more. Then there was the World Cup and all of us were so excited and keen to play. I really hoped things would turn out well for me and after the first game, everything changed - the team recovered well and it ended up as we knew it could."
Iniesta admits it is hard to describe the emotion he felt at having such a crucial hand in Spain's "priceless" victory. "It's hard to explain. All I can say is that I feel very happy, and to have scored such an important goal for everybody, to make millions of people happy - that is priceless," he said. "A lot of people follow us and suffer with the national team, so to see them all so happy is priceless."
Up until the weekend, Iniesta's most famous goal had been an injury-time strike against Chelsea at Stamford Bridge in 2009, which gave Barcelona passage to the UEFA Champions League final, where they beat Manchester United. And the midfielder is aware Sunday's goal was much more important.
"Every situation has its feelings. The joy I felt that day against Chelsea was the maximum, the same as the other day, maximum joy. But there are only a few teams lucky enough to win the World Cup and it's the biggest tournament there is," he added.
After scoring his goal against Holland in Johannesburg, Iniesta peeled off his shirt to reveal a tribute to former Espanyol captain Dani Jarque, who passed away tragically from a heart attack last year at the age of 26. "It's always been in my mind to pay tribute to him in some way," Iniesta said.
"He was a footballer and the idea came about before the Final. [Spain team-mate] Fernando Llorente mentioned it to me because some of our team-mates were doing similar things with Antonio Puerta [who passed away from a heart condition in late 2007], or some other person they cared for who isn't around anymore.
"And what a moment to pay tribute to such a great person and great friend like Dani. It was the best tribute in the best moment to make sure he remained with us."