Belgium coach Marc Wilmots bit back at questions over the style of his team's play after they completed the World Cup group stage with maximum points on Thursday.

Wilmots said Brazil haven't always played great football either after his Red Devils saw off South Korea 1-0 -- their third narrow win in a row.

Jan Vertonghen's 78th-minute winner came after Steven Defour was sent off in the first half. Belgium, who also beat Algeria 2-1 and Russia 1-0, will play USA in the last 16 on Tuesday.

"What does that mean, to play beautifully? I saw Brazil versus Croatia and I didn't think that Brazil were exceptional," Wilmots said, when asked who was playing the most attractive football.

"All matches are characterised by tactics, by physical fitness. It can change everything and what's important for me is the end result -- it's to win the match, whatever the style of play.

"We're here with the best teams on Earth... so I don't know who is playing most beautifully. We're not here for the performance, we're here to win."

Belgium's win came despite Wilmots making seven changes from this week's win over Russia, to keep players fresh for the knock-outs.

And the coach said it could take him "half-an-hour" to answer a question about why the team had not hit the heights it reached during qualifying.

"I'll try to make it short and simple," he said. "I'm here to set up a group. Everyone has played in the team except one or two players, so everyone's prepared and ready.

"What's important is to reach the knock-out stages. It's very simple: either we go home or we continue. I wanted everyone to be fresh."

He added: "Our objective is to win our matches and that's what we did, even with 10 players."