Heading into the first international break of the campaign, Atletico are the only LaLiga side with a 100 per cent record from three games.
Despite losing star striker Antoine Griezmann to defending champions Barca and captain Diego Godin to Inter on a free transfer, the Rojiblancos have looked strong under long-serving coach Diego Simeone.
The club-record €120million arrival of Joao Felix from Benfica has freshened Atletico's attack, with former striker Forlan backing them for a first league triumph since 2013-14.
"Yes. Well, we have to see," Forlan said, courtesy of LaLiga, when asked about his old team's title chances.
"I know that Real Madrid and Barcelona have great players but so do Atletico Madrid. They signed really good players, Joao Felix as I said, and Diego Costa is an experienced player, great talent.
"They've renewed the team with some great young players. They did a great pre-season and now we need to see how they do in the league. But they look really good. What they showed in the pre-season was interesting, great games against great teams.
"The derby against Real Madrid, I know it was a friendly but it was also a derby and nobody likes to lose by that kind of score [7-3].
"They're going to be fighting [for the title], they always fight. The gap is getting a little closer now. And those players that made history for Real Madrid and Barcelona, they're getting older as well. That could be an advantage for Atletico Madrid.
"Having a new team and renewing the team every season. Real Madrid and Barcelona are doing it a little slower than Atletico but they're still in great shape. Great players with experience. We have to see, but I think Atletico Madrid are in a good position to fight for the title again."
Atleti return to action away to Real Sociedad on September 14, before welcoming Juventus to the Spanish capital four days later for the start of the Champions League group stage.