The Portuguese captain joined Juventus last month in a staggering €117-million deal after nine seasons in Madrid.
During his stint, the 33-year-old won four Champions League titles as well as two La Liga crowns in a trophy-laden spell.
But Ter Stegen insists their fiercest rivals will be a serious threat when the new season begins.
“I think they have an amazing team, like every year, just like us,” he said. “It’ll be equally difficult to play against them with or without Ronaldo.
“You have to understand that this is a player who made the difference in a lot of games, but we focus ourselves on our game and we know that, if we’re confident, we have the chance to do it all.”
The Frenchman made a £52million transfer from AS Monaco to the Spanish club.
The World Cup winner was officially presented at the Wanda Metropolitano and will wear jersey No11 at his new club.
Take a look at his official presentation, below.
Speaking at a press conference in Singapore, ahead of Atletico’s pre-season encounter with Paris Saint-Germain, the Argentinian talked about the transfers expected to happen at the Wanda Metropolitano this summer and of his main striker.
Griezmann had decided to stay at the club after being linked to a move to Barcelona and his contract extension was one of the biggest headlines of the summer.
“That’s a question for him, I’m very respectful of player’s decisions when they stay and when they go, an opinion about how he feels is a good question for him,” Simeone said.
“I hope he keeps growing even more than he has until now, he has no limit, he’s important for us and is a good team-mate, surrounded by the people who form a squad which is improving.”
The Frenchman, now a World Cup winner, revealed through a video documentary – “The Decision”, his decision to prolong his stay with the Rojiblancos.
He later renewed his contract until 2023 at Atletico.