Sonia O'Sullivan is primed for a big performance at the World Cross Country Championships in the Algarve over the next two days. The event offers her the chance to make some pertinent points at the start of the countdown to the Olympic Games.

After an absence of 18 months from championship competition, O'Sullivan returns in the hope of rediscovering the form which put her in a class apart in 1998.

Some nine months after the birth of her daughter, Ciara, she seeks to prove that changed circumstances have not diminished either her capacity or her will to scale the summit of sporting achievement in the Olympic Games in Sydney in September.

The initial step on this journey will be taken at noon today when the former champion takes her place on the starting line with Gete Wami, the Ethiopian who succeeded her at Belfast last year for the long-course race over 8,000 metres.

Only after O'Sullivan has completed that race will she decide whether to take her chance in the shorter race tomorrow, which will again include many of the leading middle distance runners on the track.

O'Sullivan arrived here on Thursday to discover a course which could scarcely be better suited to her style of running. Set in golfing territory at Vilamoura, the terrain is baked hard after some high temperatures in the last week. This will suit the track specialists and the Irish athlete was enthusiastic after running on it yesterday morning.

"It's a world removed from the mud and rain in last year's championships in Belfast and it's going to make for truly-run races," she said.

"Coming here almost directly from Australia, I wasn't sure what to expect but at this point I've no complaints." Europe will be well represented by athletes of the quality of Constantina Dita of Romania, Paula Radcliffe of Britain and not least Fernanda Ribeiro, running on home territory, all capable of having an input at the finish.

Yet, inevitably, it is the African presence in the field which dominates discussions. Dita is currently the only European in the top seven in the World Cross rankings headed by the Kenyans Lydia Cheromei and Jackline Maranga.

Maranga, winner of the short race in Belfast, has since proved herself at longer distances, but as O'Sullivan sees it the two Ethiopians, Gete Wami and Derartu Tulu, are the ones to beat.

The word among the Ethiopian contingent is that Tulu is running better than at any time in her career, a point powerfully illustrated when she finished well ahead of Wami in the Ethiopian National Championships last month. Either way, however, O'Sullivan will be keeping a wary eye out for both as the race builds to its decisive stage.

One suspects that deep down O'Sullivan knows she has the potential to win. The imponderable is whether her limited racing programme of late will have given her enough of an edge to break the Africans in the latter stages of the race.

Any analysis of men's cross country championships in recent years has started and ended with the name of that remarkable Kenyan running machine Paul Tergat. Tomorrow Tergat seeks to go where nobody has been before by winning the long course championship for a sixth consecutive year.