Sergio Aguero is the undisputed King of the Premier League. His phenomenal strike rate of 109 goals in 158 games exceeds even the greats like Thierry Henry, Cristiano Ronaldo and Alan Shearer who last week hailed the Manchester City star as the only world-class player in the country.
Yet Europe has proved a different story. Although Aguero's ratio of just over a goal every other game in the Champions League looks satisfactory, closer inspection shows he is often prolific against weaker teams while struggling against City's true rivals.
Pep Guardiola left him out of City's match against Barcelona at the Nou Camp a fortnight ago and Tuesday night's return game at the Etihad is important for the Argentine to show he deserves to be mentioned in the same breath as Luis Suarez or Neymar, let alone Lionel Messi.