Atletico Madrid forward Antoine Griezmann believes he would not be considered among the best in the game without the guiding hand of head coach Diego Simeone.
Griezmann joined Atletico from Real Sociedad in 2014 and has since become a far more prolific operator.
The 25-year-old France international has 73 goals in 139 appearances for Atleti, set against 52 in 202 for Real.
"He's changed me. He's brought so many things to my game that it's hard to even begin to say what they are," he told FIFA.com.
"Let's just say that I wouldn't have been regarded as one of the best players in the world if it weren't for him.
"More than anything he's helped me to be more effective in front of goal, to take every chance that comes my way, and, of course, to run and run and work hard for the team.
"You can't make it at Atletico if you don't do that."
It has not all been plain sailing for Griezmann under Simeone, with both men hit by a heart-wrenching defeat on penalties to city rivals Real Madrid in last season's Champions League final.
Griezmann missed a spot-kick in normal time, while Simeone - evidently devastated in the aftermath at San Siro - opted to shorten his contract with the LaLiga club by two years in September.
Manchester United have been linked to a mega-money move for Griezmann at the end of this season and, although Simeone insists his altered contract status changes nothing for him at Atletico, speculation over his own future continues.
Nevertheless, Griezmann credits Simeone with being an important guiding influence in the aftermath of the final defeat, urging him to go one better this year.
"He said some things that were very important to me, because I felt it was my fault we lost because I missed a penalty," he added, with Atleti returning to Champions League action at Bayer Leverkusen in the last 16 next week.
"He came up to me and told me the opposite was true; that I'd been vital to the team, that I shouldn't worry about it and that it was time for us to start working hard again to get back into the final."