Barcelona playmaker Lionel Messi admits he went through "many problems on and off the pitch" last season.
The 27-year-old failed to pick up a trophy for club or country and also faced charges of tax evasion.
"It was a challenge for me to return to be the player I had been in previous years," he said before Saturday's La Liga visit of Malaga.
Messi scored 41 goals in Barca's last campaign, compared with 60 in 2012-13 and a European record 73 in 2011-12.
Messi also suffered further on pitch disappointment with his country, as Argentina were beaten in the World Cup final by Germany after extra-time.
|Champions League top scorer: 75||La Liga top scorer: 269|
|Barcelona's top goalscorer: 376||Most goals in a La Liga season: 50|
|Most goals in a season: 73||Most consecutive La Liga matches scored in: 21|
|Most Ballon d'Or titles: 4||Most goals in a single European Cup game: 5 (joint with Luiz Adriano)|
|Most European Cup top scorer awards: 4 (with Gerd Muller)||Most goals in Clasicos: 21|
|Most La Liga hat-tricks in a season: 8||Most goals in Club World Cup: 4 (held jointly with Denilson)|
|Most goals in a calendar year: 91|
"The truth is that I, since the beginning of this year, tried to start the best way. I knew that I was not coming from a great year," he said.
"I passed through many things, through many problems, not only on but also off the pitch."
Barcelona sit just a point behind leaders Real in the title race, after putting together a streak of 11 wins in all competitions since a 1-0 La Liga defeat at Real Sociedad on 4 January, matching their best run under former coach Pep Guardiola in 2008-09. Messi has 37 goals in 33 games so far this season.
They are also on the verge of a place in the Copa del Rey final, and through to the Champions League last 16 to face Manchester City on Tuesday.
"We must play for every title," he said. "This is Barca and we are forced to play for everything. Sometimes you make it and sometimes you don't. Last year we didn't win anything and this year we hope to be able to achieve great things.
"Manchester City are a team with great players who want to go to the quarter-finals. They have been trying to achieve for a long time.
"They have spent a lot of money and have a good team, bringing good players. So they come to win, and it will be a very even match, where the minor details will prevail."