Manchester United convincingly beat Porto 3-1 in the opening game of the Amsterdam pre-season tournament, although they ended the match with nine men after Wayne Rooney and Paul Scholes were sent off.

Rooney was shown a straight red card four minutes before the break after he caught Pepe in the face with his forearm while jumping for a high ball.

Scholes followed midway through the second half after a clumsy tackle.

"It was a ridiculous decision," United manager Alex Ferguson said of Rooney's sending off when talking to Sky Sports.

Rooney was also sent off during England's World Cup quarter-final defeat by Portugal in June for stamping on Chelsea defender Ricardo Carvalho.

Scholes had opened the scoring for United after 10 minutes when Ryan Giggs picked him out from a corner and he shot into the net from just outside the penalty area.

Rooney then doubled the lead eight minutes later with a fine chip over Porto's goalkeeper Helton.

Ole Gunnar Solskjaer, who played only three league matches in the last three seasons because of injuries, added a third goal after 74 minutes.

Central defender Pepe scored Porto's consolation goal four minutes later with a fierce shot form 20 metres.

United's new signing Michael Carrick, who cost an initial £14 million sterling from Tottenham Hotspur earlier this week, played his first match for the club.