Samir Nasri has claimed Yaya Touré is not recognised as the world's best midfielder because he is from Africa, and says if the Ivorian was Brazilian or Argentinian "everyone will talk about him".

Touré scored the equaliser in Manchester City's 3-1 League Cup victory over Sunderland on Sunday, with an impressive 30-yard shot nine minutes into the second half. The goal – which was followed by others from Nasri and Jesús Navas – was Touré's third for City at Wembley, following the winners in both the 2011 FA Cup semi-final and final, and his 17th of the season.

Nasri believes the 30-year-old's display was the latest evidence that he is the best in his position. "I'm tired to talk about Yaya. You should know now [how good he is]. If he wasn't African everyone will say he's the best midfielder in the world," said the Frenchman. "He can do everything, he can score goals, he can defend, he can attack. When he gets the ball he is so powerful.

"You should just admire the way he plays because he's a great player. I might be a little bit biased because he's my friend, but for me he's in the top three of the best midfielders in the world. Of course it counts against him being from Ivory Coast. If he was Argentinian or Brazilian everyone will talk about him, everyone. You have some Brazilians or Argentinians, I don't want to say anything wrong, but just because they are from this country you pay them £40m or £50m.

"A guy like Yaya, he [has] won every trophy, he is always there. Tell me one defensive midfielder who can go forward like him who can score 16 or 17 goals in a season. Tell me one and then we can talk."

Nasri refused to draw comparison with his former France team-mate Patrick Vieira, considered one of the finest midfielders of his generation. "I played with Patrick at the end of his career. I didn't play with him when he was at Arsenal," said Nasri. "OK, I watched every game and I don't know, Patrick was amazing."

The triumph means Manuel Pellegrini's team could still claim a domestic treble. Wigan Athletic, who beat City in last May's FA Cup final, are next up in Sunday's sixth-round tie, and the two league games in hand over the Premier League leaders, Chelsea, plus superior goal difference, mean the six-point deficit could be overhauled.

José Mourinho's side hold no fears for Nasri. "I'm not scared about Chelsea or the league," he said. "There is plenty more to play and everyone is going to have difficult games and if we win our two games we are going to be top of the league. It's better not to talk but to act on the pitch.

"We are there in the league, if we win our two games in hand we will be top with Chelsea. It's going to be tough until the end because Liverpool are still there. And we play Wigan home in the FA Cup and it's going to be a good time to have revenge. After that the semi-final it's at Wembley so we don't have a weird place to play away, it's in one place."

Of his goal against Sunderland, Nasri added: "It's what they pay me for and bring me to the club [for]. It's about time to show them what I can do. Everyone at the club has been amazing with me, believed in me and when you have this feeling your confidence is really high and that's why you want to do good for them."