Luis Suarez made an immediate impact at Atletico Madrid by scoring two and setting up another as they trounced Granada 6-1 on Sunday.
The striker joined Diego Simeone's side from Barcelona in a €6 million (£5.5m/$7m) deal on Thursday after a move to Juventus fell through.
The 33-year-old came off the bench to make his debut for Atleti when he replaced Diego Costa in the 70th minute with his side 3-0 up.
The Uruguay international needed less than two minutes to contribute to the scoring as he set up Marcos Llorente to make it 4-0, knocking it on for the midfielder to slot home.
Suarez then seemed to have won a penalty for the Rojiblancos, but a VAR check saw the decision overturned. But he would follow that up by netting his first goal for his new club when he rose to meet a cross from Llorente and nodded past Rui Silva.
He then scored a second deep in injury time, finishing after playing a one-two with fellow substitute Vitolo.
Suarez is now the first Atletico player to score and assist on his debut in the 21st century, and the first debutant to net a double for the club this century as well.
Suarez, who enjoyed a successful six-year spell at Barcelona, signed a two-year deal with Atletico after falling out of favour at Camp Nou.
Reports claimed Ronald Koeman had decided the former Liverpool and Ajax star had no place in his plans for the team, but the Dutch coach suggested this week that the decision to offload Suarez was made before his appointment.
“It seems that I have been the villain of this film, but before I arrived here, some decisions had already been made and I supported those decisions – it wasn't up to me," he said.
“I only showed respect to Luis Suarez as a person and a player. I told him that if he stayed it would be difficult for him to play but that he would be part of the squad.”
Sunday's clash was Atletico's first of the new La Liga campaign and they are back in action on Wednesday when they travel to Huesca.
Simeone's team finished third in the Spanish top flight last season, 17 points behind champions Real Madrid.