Mercedes admits it will be under pressure to produce a competitive car now it has signed Lewis Hamilton for the 2013 season.The 2008 world champion ended a six-year spell at McLaren to replace Michael Schumacher at Mercedes after signing a three-year deal with the Brackley squad.Mercedes has so far failed to field a car strong enough to fight for wins regularly, although Nico Rosberg took victory in the Chinese Grand Prix earlier this year.Team CEO Nick Fry is aware than signing a driver like Hamilton will raise the pressure on Mercedes to make sure it can deliver a strong car, as there are no doubts about the Briton’s skills."I think it’s a clear indication of the aspirations of the team. We’ve had probably one of the greatest drivers of all time driving for us, who was clearly in age terms reaching the later part of his career when he arrived with us,” Fry told AUTOSPORT."In order to do well in Formula 1, you’ve got to do well in every respect. You’ve got to have the best technology, you’ve got to have the best teamwork, you’ve got to have the best management and you have to have the best drivers."[Hamilton’s arrival] is very exciting for the team and also puts a lot of pressure on because Ross [Brawn] has to provide him with a very good car."He can’t win with a car which is duff. He can win with a car that is not quite the best, but the competition is such that you can’t bridge a huge gap.”Fry reckons Hamilton is in the same category as Ferrari driver Fernando Alonso when it comes to winning with a car that is not the class of the field.He believes world champion Sebastian Vettel is yet to prove that despite three titles in a row.