Fernando Alonso says McLaren require perfection if they are to score points at the power-sensitive Spa circuit.

Even after a Honda upgrade, a lack of horse power is expected to hamper the Woking outfit once again.

Nonetheless, Spa is notorious for its fickle weather conditions, and rain could propel the team up the running order.

Alonso, then, is hoping for mixed conditions on Sunday, but acknowledges that McLaren have no room for error.

"Hopefully the weather will help us," the Spaniard said. "Rain or mixed conditions in the race will help us, a good qualifying, start and strategy.

"We need to make everything perfect to score points. We need to focus and concentrate."

Prior to the weekend, the drivers were relishing the prospect of tackling the iconic circuit in 2017's high-downforce machinery.

F1 veteran Alonso says every lap is 'magic' but found himself slightly underwhelmed.

“It was not too different, I was expecting more probably," he admitted.

"In the last couple of races at Silverstone Hungary and Austria I think the cars performed very differently compared to last year and they were much quicker.

“For us here it was not the case here unfortunately, you lose so much on the straights and you gain in the corners but the lap time was not too different.

"It is always fun, it is probably the best circuit in the world so every lap you do here is magic."