'Going to Chelsea? It looks like it' admits Costa
The 25-year-old made his return to the pitch against El Salvador in the United States, playing his first game since the UEFA Champions League final, when he limped off with a hamstring injury.
After the match, Costa appeared to confirm he will be transferred to Chelsea from Spanish champions Atletico Madrid.
"Am I going to Chelsea? It looks like it," he said.
Costa had a breakthrough campaign in the 2013-14 season, scoring 27 goals in La Liga as Atletico won their first league title in 18 years, while he hit the back of the net eight more times in the Champions League as Diego Simeone's men reached the final.
The Brazilian-born forward has been consistently linked with a move to Chelsea before next season.