Nico Rosberg has said that he remains optimistic that Mercedes can resist the challenge being posed to its fifth place in the F1 constructors' championship, despite Sauber closing in at Suzuka last weekend.

With Kamui Kobayashi claiming his first F1 podium on home soil and neither Mercedes driver adding to his tally, Sauber took another 15 points off the Three Pointed Star's advantage, closing to within 20 points with five races remaining on the 2012 schedule. Rosberg, however, can point to his first lap retirement - as the innocent victim of an accident sparked by Romain Grosjean turning Mark Webber around at turn one - as being a major factor in Mercedes' inability to maintain the cushion, and believes that the W03 will also be better suited to the Korea International Circuit this weekend.

"Personally, I'm looking forward," he insisted, keen to put Japan behind him, "I want to try to maximise the points that we can get and I'm convinced we can [keep Sauber at bay]. There are still a lot of points to be had in the next few races and that isn't going to be a concern.

"Already, in the race in Japan, things were looking better. Michael [Schumacher] put in a consistent pace there and, for sure, this track should suit us more [than Suzuka with] all the conditions, all the circumstances, the long straights and everything. I'm definitely looking forward to it and I'm confident that we can do better again."

Mercedes turbulent form over the second half of the season, which sees it sitting 103 points behind fourth-placed Lotus, also makes it difficult to predict Rosberg's place in the pecking order, and the German himself admits that not knowing where he is going to fit in makes each weekend a journey into the unknown.

"In our situation, it's an extra motivation, because I come here and I'm not sure that I'm definitely going to be in the same position as in Suzuka," he explained, having qualified only 13th at the Japanese circuit, "There's a chance that I will be able to be a lot further up and fighting for much better positions, so it's quite a nice thing."