The alleged incident took place in 2009, before Costa made the move to Europe. The story goes that in the most important game of the season, a decision made by he and his Gremio team-mates directly impacted the race for the league title.
"We went with the reserve team to play against Flamengo. Had we won, Internacional would have lifted the title. I was dribbling on one side, [then] on the other, but still far from the goal. It was a difficult game to play, I could not give it all myself and it was bad, but I had to play to avoid winning. In the end, we lost 2-1 and eveyone celebrated," Costa told journalist Thiago Asmar.
The reasons the Brazilian gave for his team-mates "playing not to win" were simple: "What if we won? We would not have been able to leave because the Grêmio fans wanted to kill us, it would have been a stain for the history of the Grêmio, give the title to the Internacional, and if we had beaten Flamengo, we would have died."
Furthermore, Costa revealed that the Gremio squad received a piece of advice from the club's hierarchy before the game, no orders, merely advice. "It's normal that club staff visit the dressing room, especially ahead of important games," he explained. "Flamengo were battling for the title and the Maracana was full. They told us to do as we wished, that it was our responsibility, but that if we won people were going to block the route to the airport and we wouldn't be able to leave."