Diego Simeone believes Jan Oblak's dedication since he joined Atletico Madrid has helped him develop into one of the world's best goalkeepers.

Oblak signed for Atletico from Benfica in July 2014 and initially took a little while to settle, with rumours at the time even suggesting the club's coaching staff had reservations about him.

The Slovenian picked up an injury soon after his move and had to play second fiddle to Miguel Angel Moya, with his debut producing an alarming performance in a 3-2 Champions League defeat to Olympiacos.

But since, Oblak has developed into an exceptional goalkeeper and Simeone believes he is among the world's most effective stoppers.

"He [Oblak] is one of the best goalkeepers in the world," Simeone told reporters ahead of Atletico's LaLiga clash with Alaves on Saturday.

"He has been working since he arrived to reach that place. There is collective defensive work that has helped the goalkeepers that we have had.

"It happened for [Thibaut] Courtois and now it is happening with Oblak. Beyond that they are great goalkeepers, and there is a collective work that helps us in defensive situations."