Leo Messi, Diego Costa and the stars of the Champions League’s sweet sixteen – in pictures

Sergio Aguero, Manchester City. What Ian Hawkey says: 'City's injury list denies them the services of three senior strikers: Stevan Jovetic, Edin Dzeko and, most importantly, Aguero'. (Photo: Paul Ellis / AFP)

Diego Costa, Chelsea. What Ian Hawkey says: 'Chelsea have several reasons to believe they are stronger now than they were last March'. (Photo: Darren Walsh / AP Images)

Zlatan Ibrahimovic, Paris Saint-Germain. What Ian Hawkey says: Worryingly, 'the French champions have not taken control of Ligue 1'. (Photo: Franck Fife / AFP)

Cristiano Ronaldo, Real Madrid. What Ian Hawkey says: 'Madrid thrashed Schalke 9-2 last season in what was festival for the so-called BBC strike force - Benzema, Bale and Cristiano. If anything, Madrid now look stronger'. (Photo: Kai Forsterling / EPA)

Kevin Prince Boateng, Schalke. Ian Hawkey says: 'This was the tie Roberto Di Matteo really did not want as his reintroduction to the knockout stages'. (Photo: Patrik Stollarz / AFP)

Arjen Robben, Bayern Munich. What Ian Hawkey says: 'Pep Guardiola is wised up and warier of the type of ambush Real Madrid prepared for Bayern in last year's semi-final'. (Photo: Alexander Hassenstein / Bongarts / Getty Images)

Luiz Adriano, Shakhtar Donetsk. Ian Hawkey says: 'This was supposed to be the season where Shakhtar's authority in European football was challenge and brought down ... we are still waiting'. (Photo: Gleb Garanich / Reuters)

Alexis Sanchez, Arsenal. Ian Hawkey says: 'Stylists against stoics, and perhaps more of a test or Arsenal than they might imagine'. (Photo: David Klein / Sportimage)

Dimitar Berbatov, AS Monaco. Ian Hawkey says: 'Berbatov returns to London, where he delighted English audiences for Tottenham Hotspur for a few seasons'. (Photo: Valery Hache / AFP)

Carlos Tevez, Juventus. Ian Hawkey says: 'How will a long-in-the-tooth Juve defence handle the counter-attacking speed of Dortmund?' (Photo: Marco Bertorello / AFP)

Son Heung-min, Bayer Leverkusen. Ian Hawkey says: 'Leverkusen probably do not have the tools to ask hard enough questions to Atletico over 180 minutes'. (Photo: Federico Gambarini / AFP / DPA)

Jackson Martinez, FC Porto. Ian Hawkey says: 'Porto will eye this tie as a good opportunity to make good their reputation as their country's best ambassadors in the Champions League'. (Photo: Francisco Leong / AFP)

Ian Hawkey's analysis of the eight matches from the Champions League last 16 and a nod to the star player for each squad.