Each afternoon, in the week before tomorrow's inaugural Malaysian Grand Prix in Kuala Lumpur, the skies above the twin spires of the world's tallest buildings turned the threatening hue of gun metal, thunderheads rumbled and roiled and within minutes tropical rains spilled down as if the gods were taking a power shower.

As the Formula One championship arrives in Asia for the most finely balanced denouement in 13 years, even the elements are conspiring to hone that knife-edge to razorthin precipitousness.

Not since the final round of the 1986 championship, when any of three drivers - Alain Prost, Nigel Mansell and Nelson Piquet - could have taken the title has the race for the driver's title been so close.

Malaysia, it seems, can sense it, and as it plays host to its first grand prix it has gathered a set of unpredictable elements sure to send the pressure on the chief protagonists sky-rocketing into heights which dwarf the Petronas towers.

Last week, out of the bilious skies, those protagonists began to shuttle in. The favourites: McLaren's Mika Hakkinen and Ferrari's Eddie Irvine. The stalking horses: Jordan's Heinz-Harald Frentzen and second McLaren pilot David Coulthard. And finally, perhaps the ultimate spoiler and Ferrari's secret weapon, Michael Schumacher.

Press-ganged into service by a desperate Ferrari president, Luca di Montezemolo, Schumacher will resume his Formula One career just a few score miles from the shores of the Straits of Malacca, sea lanes once prowled by the most notorious pirates and buccaneers; Ferrari will be banking on the German steaming in to earn Eddie Irvine the booty necessary to take the championship to a do-or-die finish in Suzuka in a fortnight.

McLaren, though, are refusing to acknowledge the presence of Schumacher in their waters. While Hakkinen has suffered through a tempestuous season of technical and personal failures, the defending champion was earlier this week still insisting he is firmly on course for back-to-back championship wins. "The whole team has worked hard this season and the only reward anyone wants is the championship," he said. "We are in a better position than Ferrari now and the whole team will be up for the challenge. We have made mistakes along the way, but we can still override anything bad with two more wins."

Hakkinen's team co-ordinator, Jo Ramirez, was even more insistent that the title is within reach tomorrow afternoon, confidently predicting the team would start with the advantage of pole position. "We have every confidence that one of our drivers will take pole position for the race," said Ramirez. "That has nothing to do over-confidence, our track record over the year is impeccable. We've started on pole in 11 of the 14 legs."

A few weeks ago, the battle for pole position and, from there, to the first corner would have occasioned major headaches in the McLaren garage. But, finally acknowledging that Schumacher's return will have an effect on tomorrow's race, Ramirez admitted that David Coulthard's recent, stubborn and divisive adherence to his own championship chances is likely to be ruled out tomorrow. "I think he (Coulthard) will have to step back," he said. "Furthermore, with the return of Michael Schumacher to help Irvine, it will be very difficult for Hakkinen to win it on his own."

Just how much Schumacher can contribute to Irvine's race is, however, open to question. Announcing his intention to race in Malaysia and Japan, the German said he had "no more problems" with his legs and that he felt "a lot better than I had thought".

Just five days earlier, though, the German had written off any return, saying that his knees had inflamed almost immediately during testing. Despite Ferrari's insistence that Schumacher's condition has shown "a big improvement", and after an audience with the Pope, such a miraculous recovery is highly unlikely and it is clear that the erstwhile Ferrari number one is far from fit.

In this case, Irvine's best hope is that Schumacher can secure a front row grid position and then blockade Coulthard until the Irishman can pass, and thereafter provide a shield to stave off any threats to his position.

Schumacher's role, of course, depends on Irvine's own performance in this afternoon's qualifying session. Irvine's recent qualifying form has, however, been poor, slumping from second in Hungary to sixth at Spa, eighth at Monza and two weeks ago the nadir of ninth at the Nurburgring.

Since the tight confines of the Hungaroring and the suitability of the F399 to such arenas, Irvine has struggled to find the right set-up in the contrasting environments of Spa and Monza. But he will surely gain from Schumacher's input this weekend on a circuit which Ferrari are hoping will treat their car better.

Predicting the suitability of the Sepang circuit is, however, based solely on the informed guesswork of computer modelling. The track is virgin territory, unraced and untested, and while simulations will have taken the edge off both Ferrari and McLaren's ignorance, the quirks of its 5.5 km surface could play a significant role tomorrow.

But, while the circuit's quirks may have an influence on the performance of the cars, it's the possibility of rain that will edge the penultimate round of the championship into the realm of high drama. Downpours turned the grid on its head at Magny Cours. The European Grand Prix was rendered a free-for-all by precocious showers.

What effect will rain this afternoon and tomorrow have? Schumacher is its undoubted master, Hakkinen has lost both wet races this year, Frentzen won one of those and led the other.

And Irvine? In the midst of the title tempest the Irishman had last week retreated into guarded monosyllables. Malaysia throws up yet another surprise.