West Ham United boss Sam Allardyce has paid tribute to Manchester United manager Sir Alex Ferguson.

Ferguson won his 13th Premier League title this week.

"You're always chasing the master and he has been the master for so long - it is difficult to sustain success against him," Allardyce told a press conference.

"Whenever he has a challenge, he may lose out once, but he comes back with flying colours. He's had it with Chelsea and before that Arsenal."