LONDON, England - Mercedes is playing down its chances of repeating Nico Rosberg's maiden victory at Shanghai in 2012 in next Sunday's 2013 Chinese Formula 1 GP.Motorsport director Toto Wolff said that triumph did not mean the team could realistically target the same result in China despite an encouraging start to the season after the arrival of 2008 champion Lewis Hamilton.Hamilton quit McLaren to take now retired seven-times champion Michael Schumacher's race seat. The Englishman has suggested, after impressive season-opening events in Melbourne and Kuala Lumpur, that Mercedes was now the second-best team behind Red Bull.'START FROM ZERO'Wolff added: "One year on from Nico's win a lot of people will be asking whether it is something our team can repeat in 2013 but, as they say, yesterday's home runs don't win today's games."We start again from zero and need to work hard to adapt the car to suit the circuit and the tyre compounds we have available in the conditions we will find on the track next weekend. Then we will see where we stand, relative to the competition."We've made a solid start to the season in the first two races with Nico and Lewis both performing at a very high and equal level. The development race will be critical so we have more new parts planned for China. Our aim has to be to improve on our good start to the season and continue scoring good points in both championships."'UNIQUE SITUATION'Hamilton had his first podium place with Mercedes in March in Malaysia: he was third behind feuding Red Bull duo Sebastian Vettel and Mark Webber but admitted he was not expecting his team to emulate 2012's performance."Mercedes was in a unique situation then and got everything right," he said. "The tyres are different this year, so you have to anticipate that it's going to be a little bit different there for us."Walking off into the distance is probably not going to be the case. If the car works well there and we get a similar result there it'll be amazing."