But in doing so the American was made aware of another Jamaican challenger other than Bolt as 20-year-old Yohan Blake produced a late challenge which earned him a massive personal best of 19.78, almost a second better than his previous mark of 20.60.

Gay's time equalled that of compatriot Walter Dix as he earned a narrow victory over the former world champion at the Eugene Diamond League meeting earlier this month.

Gay was unable to exact any revenge tonight due to the late withdrawal of his US rival due to "financial reasons".

The circumstance had clearly frustrated Gay, but he appeared to have carried out his intention of running the race as if Dix was in it, establishing a clear lead into the final straight and hanging on despite a strong challenge over the final 20 metres from lane eight, where Blake was offering further evidence of his high promise.

"The problems I had earlier this season are now behind me," said Gay, who will now concentrate his efforts on the 100m, with a likely race against Bolt and Asafa Powell in Stockholm.

"The new track in Monaco is very fast - this result is a combination of the track and my speed.

"But I am very tired now..."

The women’s 100m also produced a top class performance as America’s Carmelita Jeter earned revenge for her defeat in Eugene by defeating Jamaica’s Veronica Campbell-Brown, recording a season’s best of 10.82.



Campbell-Brown, who had run a personal best of 10.78 in Eugene, was second in 10.98.

Kenya’s Silas Kiplagat made his mark in a top class 1500m race which saw the lead change hands twice in the final straight, winning in 3min 29.27sec,  the world’s fastest time this year.

Until Kiplagat’s late surge it looked as if Morocco’s Amine Laalou had done enough to win, but he had to settle for second in  a personal best of 3.29.53 after passing the Kenyan who had led into the bell, Augustine Choge, who finished third in 3.30.22.

"I knew I was in great shape," said Kiplagat, who is coached by the great Moses Kiptanui. 

"I knew I could run that fast."

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