Antoine Griezmann promised to mount a LaLiga title challenge with Atletico Madrid after making "the hardest decision of my career" to reject Barcelona.

The France striker was heavily linked with a €100millon switch to Camp Nou, but announced that he would be remaining at Atleti via a documentary broadcast on Spanish TV in June.

Griezmann scored 19 league goals in 32 games last season, before netting four in seven World Cup outings to help France claim the Jules Rimet Trophy for the second time.

READ: Perez pays tribute to Ronaldo and Zidane

The 27-year-old opened up about the impact the decision had on his life and the interest Atleti showed in his wellbeing throughout an emotional time.

"Like I said, I was given love. Everyone wanted to know how I was doing. It was the hardest decision of my career. I woke up my wife at 3am to talk about it," he told Telefoot .

Atleti finished second last season, but has made a sluggish start to this campaign, winning two of its opening five LaLiga matches to sit fifth.

ALSO READ: Simeone hails Atleti's best display of the season

Griezmann has just a goal to his name in all competitions, but remains confident that Diego Simeone's side can challenge Barcelona and Real Madrid for the title.

He also pledged to contribute to an improvement in the Champions League after Atleti was eliminated at the group stage last season, despite going on to win the Europa League.

"In the Champions League we will try to do better than last year when we did not reach the knockouts. It was in a large part my fault because I was not good mentally. In the league, we will try to stay with both [Barcelona and Madrid]," he said.