Nico Rosberg will switch to his fourth and final new engine for this weekend’s Singapore Grand Prix. The move follows his engine failure three laps from the end of the Italian Grand Prix nearly two weeks ago. There the German was forced to run an older-spec engine after the latest version Mercedes introduced for Monza encountered cooling problems in his car. The team have since repaired the issues with that engine, but are understood to be concerned that Singapore’s very demanding conditions might expose any further reliability weaknesses, and so Rosberg will use his fourth and final allowed power unit for the season. Rosberg stands 53 points behind his teammate Lewis Hamilton in the championship, losing 25 in the last race due to the late retirement, and now his chances of narrowing the gap might have worsened. Notwithstanding any reliability issues for his British rival, Rosberg may have to conserve his remaining engines in the remaining seven races or face grid penalties for using more than the allocated four engines per driver for the season. Despite his recent misfortune, the 30 year-old refused to concede the championship race is already over. "I have the chance to keep believing or not and I have chosen to keep believing because it is going to help for the next couple of races and historically in sport anything can happen”, he said. "There are still seven races to go, lots of points, so I keep pushing. With the car that we have its possible to win every race weekend which is a great feeling so focus on race weekends and then see what Lewis does.” Still, he admitted the situation was more favourable to him in 2014 than this year. "I want to win the championship. The feeling last year in Singapore was a lot better than now as I had 20-something points the other way. I much preferred that one."