Is this the beginning of the end for the 'big four'?

Djokovic, Federer, Nadal and Murray

After last year’s ‘wacky Wednesday’ at Wimbledon, which saw a clear-out of seeds in both draws, the US Open upped the ante with ‘surreal Saturday’. The craziest afternoon of tennis in recent memory left us with a men’s final featuring two new faces – Kei Nishikori and Marin Cilic – and inflicted the heaviest blow yet on the hegemony of the ‘big four’.

It is an extraordinary statistic that the last 38 grand slam finals have all featured at least one member of the elite, in Roger Federer (25 appearances in all), Rafael Nadal (20) and Novak Djokovic (14). Meanwhile Andy Murray has been a slightly less essential member of the chain, while still amassing seven finals of his own.

But both Federer and Djokovic were eclipsed on Saturday to set up the most surprising final since at least 2005, when Marat Safin played Lleyton Hewitt at the Australian Open. Or is that a bad comparison, since both those men were already major champions?

Better perhaps to go back to the 1997 US Open final, when Britain’s Greg Rusedski faced Pat Rafter of Australia. That was the last time that two players from outside the top ten reached the climax of a major tournament. And that was a different era, when the top players were not as phenomenally well prepared or consistent as they are now. There is a genuine argument that tomorrow’s meeting between the world numbers 11 (Nishikori – who also happens to be the first Asian man to play a major final) and 16 (Cilic) is the biggest bolter in history.

Nishikori went first on Saturday, looking to pull off one of the toughest feats in tennis: a best-of-five-set victory over Djokovic on a hard court. On a day of unrelenting heat and humidity, his efficient style may have helped him. Nishikori is relatively tiny for a top-20 tennis player, standing less than 5ft 10in tall and weighing under 11 stone. But he stands up high in the court, taking the ball early and cutting off the angles.

A heavy rainstorm held up play before it was time for Federer’s turn. With his main rival out of the way, the second seed must have seen an opportunity: could he seize an 18th major title here in New York, and so move further ahead of Nadal in the all-time standings?

The answer: no. And the reason did not lie in Federer’s shortcomings – his statistics of 28 winners to 17 unforced errors were more than respectable – but in Cilic’s carefree power. The Croatian used to be known for a fragile mentality, having squandered a lead of a set and 5-1 against Murray here in his last appearance at the US Open, but the arrival of Goran Ivanisevic in his coaching set-up seems to have driven him on as strongly as Ivan Lendl once did for Murray.

Cilic was ridiculously powerful and error-free in a display that ended when he fired down three aces in the final game to complete a 6-3, 6-4, 6-4 victory in just 105 minutes. Some observers felt that Federer might have been half-a-step slower than usual, after needing five sets to subdue Gael Monfils on Thursday night.

The world of tennis certainly has been reshaped by this upheaval of the established order – although it is difficult to say how world TV audiences will respond to a final featuring two men they had barely heard of before the tournament though the whole of Japan and Croatia will be watching. You could have got odds of at least 50-1 on either, coming into Flushing Meadows. And if you had combined the two men together, you would have been able to name your own price.