Nothing quite like it so far this season. Tonight in Oslo Sonia O'Sullivan will dip her toe into deeper waters. Just how far she has travelled along the road to her full racing capacity was not seriously measured by the two-mile world record run in Cork on June 26th or by her opening two races of the season at division two competitions in St Denis and Bratislava.

O'Sullivan's preparatory runs are over and tonight she faces her toughest opposition since last summer's World Championships.

The Bislett Games is the first of the serious Grand Prix meetings and O'Sullivan will face at least three runners who have usurped her position at the summit of middle-distance running - Russian Svetlana Masterkova, Carla Sacramento from Portugal and Romania's Gabriela Szabo were all confirmed yesterday as competitors for the women's 1,500 metres event.

Masterkova, winner of both the 800 metres and 1,500 metres at the Atlanta Olympics, Sacramento, world 1,500 metres champion in Athens and world 5,000 metres champion Szabo will all be vying for a slice of the first of the IAAF Golden League pies with the possibility of $1 million at the end of it all at the Grand Prix final in Moscow in September.

Szabo ran four minutes 19.3 seconds in the mile just a week ago in Bellinzone, making her only the 10th female in history to run the distance in under four minutes 20 seconds. She will be the clear race favourite.

The newly-structured Golden League now offers a jackpot of $1 million for anyone who can win at all six meetings plus the final. The idea of International Amateur Athletics Federation (IAAF) president Primo Nebiolo, the series of meetings kicks off at the Bislett stadium before going on to Rome (July 14th), Monte Carlo (August 8th), Zurich (August 12th), Brussels (August 27th), Berlin (September 2nd) with the final being held in Moscow on September 5th.

The selected events for men are the 100 metres, 400 metres, 1,500 metres, either the 3,000, 5,000 or 10,000 metres, 400 metres hurdles, triple jump and pole vault, while the five selected events for women are the 100 metres, 400 metres, 1,500 metres, 100 metre hurdles and javelin.

While the wounds opened by O'Sullivan's disappointments in Athens have been largely closed by her double World Championship cross-country win, her track season to date has been more encouraging than exciting. The two-mile record set in the Mardyke two weeks ago was, by her own admission, one of the least difficult records on the books and was contested over a distance rarely, if ever, run any more.

More importantly, the Cork run will have strengthened the runner's confidence, not having raced before that for three weeks. Both the record and the win were clearly a tonic after a third place over 5,000 metres and a second in Bratislava over 1,500 metres and while O'Sullivan is expected to concentrate on the 5,000 metres in the European Championships in Budapest at the end of August, her schedule until the end of July does not take her over 3,000 metres.

"I feel really comfortable in the 1,500 metres at the moment. I feel really good running behind people and you get a better chance to do that in 1,500 metres rather than in a 5,000 metres race where you have to run in front. I'm definitely as good and probably better now than I was in Marrakesh at the world cross country," she said.

After tonight's run she will travel to Rome for a 1,500 metres race in the second Golden League event before taking in a 3,000 metres race in Nice at the Nikaia meeting on July 16th. At the end of the month she will travel to New York for a mile run in the Goodwill Games on July 20th.

In the other events the current American sprint queen Marion Jones will be the favourite in the 100 metres. Jones is the first woman to threaten Florence Griffith Joyner's 100 and 200 metres world records set during an astonishing few months in 1988. In time, she confidently expects to break both marks as well as the world long jump record. Jones also plans to go one better than Carl Lewis by winning five gold medals in one Olympics at the Sydney 2000 Games.

Australian Cathy Freeman, who also ran sprints at the Mardyke, is the athlete to watch in the 400 metres, while world record holder and Olympic champion Michael Johnson goes in the 400 metres with American Maurice Greene facing up to Namibian veteran, Frankie Fredericks, over 100 metres and Ato Bolden of Trinidad over 200 metres.

Britain's Jonathan Edwards, in the triple jump, and evergreen Sergei Bubka of Ukraine, in the pole vault, will typically drive up the competition to a higher gear.

World records could fall in either the 1,500 metres or the 3,000 metres. Over the shorter distance Morocco's Hicham El Guerrouj could be seriously pressured by the remarkable Kenyan Daniel Komen, while over 3,000 metres the incomparable Haile Gebrselassie is in form having set world records for 5,000 and 10,000 metres last month.