SINGAPORE - Nico Rosberg has spent hours in Mercedes' Formula 1 simulator preparing for Singapore's tricky street circuit but he still found it hard to adjust his body clock to simple things such as lunch.The German, like everyone else in the F1 paddock, has no choice but to stay on European time and become a night owl ahead of the weekend's GP under the floodlights in the south-east Asian city state.TIME DIFFERENCETaking a quick break to get some food before facing another onslaught of media interviews, Rosberg told Reuters he was still getting used to a routine dictated by a race that starts at night."That was lunch. Lunch at 8pm," he said after his plates were collected from the table. "I woke up at four this afternoon, I go to sleep at five in the morning. That's the rhythm, it's the European rhythm."I was in the gym at four in the morning before going to sleep. It's so weird."While Lewis Hamilton's contract situation continues to dominate headlines and speculation mounts that he could be ready to leave McLaren for Mercedes, Rosberg said he was not fazed by all the talk.PUSHING TOGETHER"Not at all. I follow the rumours of course, but what concerns me is the time to come," he said. "I'm proud to be driving a Silver Arrow and I'm looking forward to winning many more races with them."He added that he hoped seven-times World champion team mate Michael Schumacher, now 43, would remain with Mercedes."With Michael it works well, so I'll be glad if he stays on next year. We also push the team together very well."While he has had only one win this season, in China, and is seventh in the Drivers' championship almost 100 points behind leader Fernando Alonso, Rosberg did not think the season had been a disappointment. The win in Shanghai was the first for Mercedes since taking over Brawn GP three years earlier."Our target for this year is to do better than last year. I think we can say we managed to achieve that. Winning in China and second in Monaco were great results," Rosberg said."So it's got to be seen as a positive year. But now we've ticked that box and we have to progress further, so now our challenge is to win several races."