Belgium can justify their outsiders tag and win the World Cup for the first time, claimed attacking midfielder Marouane Fellaini who said he'll shave off his afro-style hair if they succeed.

The 26-year-old, who has said he will shave his famed afro-style hair should the Red Devils win the trophy, put aside a difficult maiden season with Manchester United after a £27.5million transfer from Everton and scored with a superb header in the 2-1 win over Algeria on Monday.

His goal couldn't have been better-timed as he seeks to convince new United boss Louis van Gaal that he is worth persevering with when the Dutch national coach takes over the reins after the World Cup.

While the Belgians, appearing in their first major championships since the 2002 World Cup, were slow to get into their rhythm they looked more like the side that went undefeated through their qualifiers by the end of the match when Dries Mertens scored the winner.

"Belgium are capable of winning the World Cup," said Fellaini. "If that proves the case I promise that I will shave my hair."

Fellaini, son of Moroccan parents whose father was a former professional goalkeeper, received rave reviews for his performance when he came on as a substitute against Algeria and with the Belgians trailing 1-0.

Former England striker turned BBC presenter Gary Lineker tweeted an ironic tweet that Manchester United should buy the Fellaini that played for Belgium.

However, Fellaini, who chose to play for Belgium ahead of Morocco, says there is no difference between his performances for his country and United, despite him failing to score a goal in the Premier League last term.

"The Fellaini of Manchester and of Belgium is the same player," he insisted.

"They bought me a year ago. There have been the good moments and the bad ones.

"I was injured, there was a change of coach (his former Everton boss David Moyes was sacked), and the team wasn't playing well. We will see next season. I will try to be better."

Fellaini said he hadn't regarded the game against Algeria as a case of proving himself.

"For me the match was not a case of answering my critics," he said.

"I don't owe anybody anything. My goal is to score for the team for my family and for the country.

"I had a difficult season but now I am at the World Cup and I am focussed on the national team."

His team-mates are bemused by the difference in his level of play for club and country and put it down to his strengths not being properly utilised at United.

"We know how to use Fellaini," said Spurs and Belgium defender Jan Vertonghen, who conceded the penalty that gave Algeria the lead.

"We do not know what is going on at his club. He is still vital to the national side.

"I know he was put under a lot of pressure by the English supporters, but with Belgium he always plays well and scores goals.

"I am happy he scored. I know how important that was to him to score a goal at the finals."