Lessons from Leverkusen? Xabi Alonso's Chelsea rebuild explained

It was in 2008 that Jordan Henderson made his Premier League debut. Chelsea – think Joe Cole, Deco and the rest – were the opposition and beat Sunderland 5-0. Two weeks later, Danny Welbeck marked his own debut with a goal for Manchester United.

If that feels like a different era, it is because it was. Barack Obama won the election to become the 44th president of the United States that month. Pep Guardiola was just starting out in management. The man in charge of Chelsea was Luiz Felipe Scolari.