Willian says his friendship with Chelsea team-mate Eden Hazard will be put to one side when Brazil take on Belgium in the World Cup quarter-finals on Friday.
The pair have played together at Stamford Bridge for the last five years, but look set to come face to face on opposing sides in Kazan.
Willian looks set to keep his place in Brazil's starting XI after impressing in the last-16 win over Mexico, while Hazard is likely to start as Belgium captain.
Ahead of their encounter on Friday, Willian said of Hazard: "He is a very humble player and I like being with him on a daily basis at club level."
"But now it is time for each of us to defend our corner and I hope to come out on top."
"He is one of the best players in the world, but now I am on a different side and I want to do everything to win."
"I know we will remain friends after."
Brazil were touted as one of the favourites to win the World Cup ahead of the tournament, but began their campaign with a lacklustre 1-1 draw with Switzerland.
However, they have reached the last eight while other fancied sides have been eliminated, and Willian believes his side are improving with each round.
"The team has evolved since the first game", he said.
"There was nervousness in that first match, a more complicated start against Switzerland, and we have grown step by step."
"I think we are at the same level as in the qualifiers."
Source: Skysports