Rafael da Silva has signed a new four-year deal at Manchester United, which will keep the Brazilian full-back the club until the end of the 2015/16 season.The 21-year-old has impressed in his four year spell at at Old Trafford, and his performances for the first team have warranted a call-up to the Brazil squad.Rafael expressed his delight at signing on at the club, saying he is 'hungry for more.'“I am so happy to sign a new contract. I love playing for Manchester United, there is a great team spirit here and a real desire to win."My time here has been unbelievable; winning two league titles, a league cup and a Club World Cup has made me hungry for more trophies. I would like to thank Sir Alex for his belief in me and I would also like to thank the fans for their support.” he told the club's official website.