Failure in the 10,000 metres would raise doubts about McColgan's future, be costly to the team and almost certainly eliminate her from consideration for this summer's world championships in Gothenburg.
The 1991 world champion and double Commonwealth Games gold medal winner's selection came about in a curious way. She has not run a track event for three years because of a succession of injuries and the assumption that if she had an athletics future it would be bound up in her marathon ambitions. Yvonne Murray would have been a more obvious choice for today's race but she opted to run the 5,000m, which she had not run for 12 years. But she has also had to miss this weekend's event because of a troublesome knee injury that she needs to clear up quickly.
So McColgan is left as the only notable distance runner in the team, female or male. A burden of expectancy falls on her today - one for which she may not yet be prepared.
Her only really impressive outing so far this year was in Basle earlier this month, when she finished second to the Ethiopian Olympic champion Derartu Tulu in a 5km road race. Her last track appearance was as far back as the 1992 Olympic Games in Barcelona, and her most competitive road race of this season was her fifth place in the London Marathon. That run was typically brave but hardly relevant as far as her ambition to run in this year's world championship 10,000m was concerned. Nevertheless, the selectors inked in her name for the European Cup team ahead of most others. It was a gamble with an athlete who of late has continually promised much and only run into problems.
In May she pulled out of a five kilometre road race against Murray and Tulu in Portsmouth because of breathing problems. "I just felt there was something badly wrong at the time," she said. She also has to contend with the psychological problem she acquired in the London Marathon when by less than half distance she realised how much her two-year struggle with injuries had cost in stamina and competitive edge. "I knew what was wrong in London; it was a lack of racing," she explained.
That absence from competition is nagging at this normally ultra-confident, vastly experienced athlete who says her motive for wanting to run here today is to prove to herself that she can achieve the qualifying standard of 32min 30sec for the 10,000m at the world championships and have a year free of injuries before next year's Olympic Games in Atlanta where she is still keen to run.
The lesson of her London Marathon performance has been absorbed and she makes no predictions about a race today that brings her up against an old adversary, the New York and Boston marathon winner Uta Pippig, of Germany. She must also face Maria Guida, of Italy, who has run 32min 10.38sec this season and had a best time of 31min 42.14sec last season. Guida could be the surprise winner today but a second or third place for McColgan would be encouraging only if she can achieve a time that might make another year of hard training worthwhile.
No race in her long and illustrious career has held such significance. She also knows that some members of the British team have not completely forgiven her for issuing a condemnatory accusation last year about the scale of drug-taking within their numbers. Although she later toned down her original suggestion that "a lot" of the British team were taking stimulants, the original insinuation has not been forgotten. An often outspoken person, she also has great courage which Britain will need in great quantities on the second day of competition here.