Mat Coch writes:

Expected to last almost two hours, Sunday's Singapore Grand Prix is one of the toughest on the calendar. That's the claim of a number of drivers who suggest the Marina Bay event is even more taxing that the streets of Monaco.

"Monaco, is more mentally challenging because it's faster," insisted Jenson Button. "It seems like it's three times as quick as any other circuit on the calendar so mentally it's very, very challenging.

"Here it's more physical. Not because of the high-speed corners, but because of the bumps," continued the 2009 world champion. "A lot of vibrations, humidity, it's the longest race, and the lights. It's very, very draining. After the race if you see the drivers it's the most tired they'll look this year."

"I would say this is one of the most difficult races in the championship," agreed Vitaly Petrov. "It's different I think to all other tracks because of the low speed corners, it's night and the humidity is high."

"Even Malaysia was not so difficult," he continued. "You don't have straights, you're always using the brakes… now we have KERS, now we have DRS, we have a lot of things to do."

With the championship within grasp this weekend, even Sebastian Vettel is weary of the circuit's challenges. "It's one of the biggest challenges we have," he admitted. "The focus has to be extremely high throughout the race. It's very hot, the humidity is very high. It's very tough for the drivers.

"In a way it's tougher than Monaco," he suggested. "Obviously I haven't been around that long - maybe you should ask Michael - but I think over the last couple of years we have resurfaced (Monaco) again and again and tried to make it smoother and better, safer. We've just been here a couple of times - this is the fourth time - but it's much rougher than Monaco in a way. It's very bumpy. At some places there's not a lot of room for mistakes - generally there's little or no run-off on street circuits but I think that given the lap is so long and there are so many corners, it's hot and it's humid, I think it makes it a tougher challenge, in a way, than Monaco."

Felipe Massa agrees that the circuit is one of the most demanding on the calendar. "You always have a different feeling coming back to this race because it's in the middle of the town," said the Ferrari driver. "It's like going to Monaco, for example, but I think here it's even more difficult than Monaco because one lap here is like two laps in Monaco because it's a very long track."

At just over 3.1 miles the lap punishes mistakes by drivers and places increased emphasis on accuracy behind the wheel. Changes to the kerbing in the first complex of corners will also punish drivers who in the past have been able to run wide without penalty. "The first three corners are important because they all flow in to each other, you can gain or lose a lot of time there if you get it wrong," Button explained.

"They've also put a new kerb in at turn two on the outside, so you can't go off and cut the corner now," he added. "It's going to be even trickier through that section; one, two, three. If you have a bad first three corners it's very tricky to pull it back on the rest of the lap."

The McLaren driver went on to single out the lights as perhaps the biggest challenge faced by the drivers. Despite 1500 projectors illuminating the circuit there are some sections which are better lit than others, according to the Englishman, increasing the challenge for the drivers.