Tottenham Hotspur have appointed former Chelsea and FC Porto boss Andre Villas-Boas as their new manager.Villas-Boas, who was sacked by Chelsea in March after less than a season at Stamford Bridge, replaces Harry Redknapp, who was dismissed by Tottenham in June."The Club is delighted to announce Andre Villas-Boas as Head Coach," Tottenham said on their official twitter feed.Spurs also considered Laurent Blanc and Ralf Rangnick, while David Moyes had been a serious contender before chairman Daniel Levy cooled his interest.Villas-Boas, 34, will be charged with creating a young Spurs side that can challenge for a place in the top four of the Premier League and qualification for the Champions League.The Portuguese was hugely successful at Porto prior to his move to Chelsea, winning the Primeira Liga, Portuguese Cup and the Europa League in his one season in charge at Estadio do Dragao.