Watch Shelter Dogs Adorably Retrieve Tennis Balls at Brazil Tennis Match

Four formerly abandoned dogs held the spotlight at the Brazil Open on Thursday, picking up out-of-bound balls during an exhibition tennis match in an initiative aimed to promote the adoption of abandoned street animals.

The trained shelter dogs, formerly strays in Sao Paulo, wore bright orange bandanas and worked to retrieve balls hit by Roberto Carballes Baena of Spain and Gastao Elias of Portugal, the Associated Press reported.

The dogs walked out onto the court with the tennis players, ranked 122nd and 140th, who played along and intentionally missed some of the balls.

Frida, Costela, Mel and Isabelle chased down the balls at the command of their trainer, Andrea Beckert, who said making the animals confident and playful was a challenge.

“These are dogs that were mistreated,” she said. “We have to make them adapt, feel the environment, the court, the noise of the balls and the noise of the people. Some are doing well, others are still a little scared.”