Sir Alex Ferguson last night accused his Manchester United team of showboating on the way to their Champions League victory over Inter Milan.
United progressed to the quarter-finals after goals from Nemanja Vidic and Cristiano Ronaldo gave them a 2-0 triumph over Jose Mourinho's Italian league leaders at Old Trafford.
But Ferguson said United were slightly lucky as Inter struck the woodwork twice, and he warned his players to wise up.
He said: 'I didn't know if I was watching a game of football or suicide! I thought we'd kill them off after the first goal but we left the door open and we were lucky to be ahead at half-time.
'We started to give the ball away and Inter should have been level.
'We try to drum into players that possession is important at this level but they forgot that in the first half.
'They started trying flicks and playing balls into space where there was nobody there.
'It was practice football and allowed Inter to get into the game. They were the better team for that period.
'But we have played a team that has played at its maximum and to get through is a big plus for us because we will be better in the next round.'
Mourinho said United could go on to win five trophies this season. He said: 'Yes, they can do it. They have the same team as they had when I was in this country but they have been together for five years.
'They are in the right moment to be at the top of their careers. They have the experience and the quality.
'They deserved to win and we have to accept that. But you do need luck in this competition and we didn't have it tonight.'
United, meanwhile, have been refused permission to wear their FIFA Club World Cup champions badge in Premier League games.
The honour was presented to Old Trafford chief executive David Gill by FIFA president Sepp Blatter before last night's match, but a Premier League spokesman said: 'We wouldn't expect United or any other club to wear a Premier League badge in the Champions League, FA Cup, Carling Cup or any other competition.'