Tyson Gay's comeback race following his reduced doping ban ended in 100 metres defeat in Lausanne at the hands of fellow American Justin Gatlin, but the high point of the International Association of Athletics Federations' Diamond League meeting was a stupendous 400m victory by Grenada's Olympic champion Kirani James in 43.74sec.
The 31-year-old former world 100 and 200m champion clocked a respectable 9.93 behind Gatlin, the 100m champion from the Athens 2004 Games, who has since served a four-year doping ban, the second of his career.
Gatlin won in 9.80, the fastest run so far this year.
Gay was returning to the scene of his last race before incurring the two-year ban that was halved by the United States Anti-Doping Agency in exchange for his "significant assistance" - he clocked 9.79 in winning this meeting in 2013.
The performance by the 21-year-old James made him the joint fifth fastest of all time along with the man he beat into second place on the night, world champion and 2008 Olympic gold medallist LaShawn Merritt, and was also a national and Diamond League record.
Merritt, who returned to the sport in 2012 after serving a two-year doping ban, ran a time of 43.92 which was the second best ever recorded without winning.
His US compatriot, the former world record holder Butch Reynolds, once lost a race despite recording 43.91.
Youseff Ahmed Masrahi of Saudi Arabia clocked an area record of 44.43 in third place, with fourth going to the Bahamas veteran Chris Brown, whose time of 44.59 improved his -35 world age record.
James's flourish in the single lap event was almost matched in the 200m by Alonso Edward of Panama, who won in 19.84sec from Jamaica's Nickel Ashmeade in 20.06.
Ashmeade's compatriot Yohan Blake, the former world 100m champion, had a relatively muted outing in what was his first Diamond League race over the distance for two years, finishing sixth in 20.48.
Ukraine's World high jump champion Bogdan Bondarenko won the latest high quality men's competition this season with an effort of 2.40 metres, taking the verdict on countback over fellow countryman Andriy Protsenko, for whom 2.40m was a personal best.
Russia's Olympic champion Ivan Ukhov was third with 2.38m, the same height cleared by fourth-placed Mutaz Essa Barshim of Qatar, who cleared 2.42m along with Bondarenko at last month's Diamond League meeting in New York.
A top quality competition was supplemented by a 2.35m clearance from Canada's joint Olympic bronze medallist Derek Drouin, and 2.32 from the United States' Olympic silver medallist Erik Kynard.
In a dramatic finish to the women's 3,000m, Kenya's Mercy Cherono overtook Ethiopia's World Indoor champion Genzebe Dibaba to win in 8 min 50.27sec, clocking a 59 second last lap.
Michele-Lee Ahye of Trinidad and Tobago was a surprise winner of the women's 100m after catching double world silver medallist Murielle Ahoure of the Ivory Coast, with both women clocking 10.98sec.
Caterina Ibarguen, Colombia's world triple jump champion,earned maximum points with an effort of 14.87m which equalled her world-leading 2014 effort from February.
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July 2014: Gay returns after halved doping ban to Lausanne, scene of his last win a year ago
June 2014: Eaton makes Diamond League history as Felix returns to 200m heights
June 2014: Barshim is Rome Diamond League highlight with high jump of 2.41m
May 2014: Rudisha finishes seventh in comeback 800m at Eugene IAAF Diamond League
May 2014: Rupp at home in Eugene as runs US 10,000m record in Diamond League