Sifan Hassan of the Netherlands broke the 23-year-old women’s mile world record on Friday when she clocked four minutes 12.33 seconds in a race dedicated to former American runner Gabe Grunewald, who died from cancer last month at the age of 32.
Hassan, 26, initially looked to be off the record pace in the rarely-run event but finished strongly to edge the 4:12.56 set by Russia’s Svetlana Masterkova in Zurich in 1996.
It was a fitting performance in an event named the "Brave like Gabe" Mile. There was a tribute to Grunewald on the big screens at the stadium before the race and once it was underway, Hassan, who moved to the Netherlands after leaving Ethiopia as a refugee when she was 15, was always in control.
“I knew I could run fast, but the first 800 was a bit slow, so after that I wasn't thinking it would be a world record,” said Hassan, who took more than two seconds off her previous best for the distance.
"When I crossed the line I was so surprised," she added after clocking a 62 seconds final lap.
"After you run the last 400 like that, and set a world record, it gives you so much confidence over 5,000m.
"I want to double over 1500 and 5,000 in Doha (at the World Championships in September) and the way I finished the last 400, it's amazing.”
Hassan's was not the only classy middle-distance performance of the night as Nijel Amos ran the fastest 800 metres seen since the 2012 Olympics as he posted one minute 41.89 seconds.
Nobody has gone under 1:42 since the memorable final in London seven years ago when Kenya's David Rudisha set the current world record of 1:40.91 and Botswana's Amos ran his own best of 1:41.73 to take the silver medal.
Amos followed the pacemaker through halfway in 49 seconds on Friday and held on strongly on a perfect night for the distance, with warm, wind-free conditions.
Cheruiyot Rotich of Kenya chased him all the way and posted his own personal best time of 1:42.54 as the first nine finishers clocked their fastest times of the season.
"I did an impossible session on Tuesday and after that, I knew I could run 1:41," said Amos. "The world record is not in my mind but if I'm patient, it will come."
Those fireworks meant that, for once, the men’s 100 metres was not the biggest race of the night – though it was still an excellent one as Justin Gatlin won it in 9.91 seconds, edging fellow Americans Noah Lyles (9.92) and Mike Rodgers (10.01).
"It's all about putting together a good technical race, to use my experience," said Gatlin, defying all the traditional rules of sprinting at the age of 37.
"It feels great to beat these guys. This season is surreal, I can't believe I'm still winning here after more than 20 years. Noah is a great runner, so every time I race him, I'm excited."
American Kendra Harrison won an exciting 100m hurdles in a season’s best 12.43 while Diamond Trophy holder Shaunae Miller-Uibo was a clear winner in a strong field in the 200m in 22.09.
In a chaotic men’s 400 metres there was a false start and Jonathan Jones of Barbados did not hear the recall.
Jones ran the entire race on his own, while Colombian Anthony Zambrano ran 200 metres, with neither man able to take part in the restarted race a few minutes later.
American Kahmari Montgomery, who made the false start, was allowed to start the race, which was won by Steven Gardiner, who also ran on for a while during the initial mess, in 44.51.
"I covered almost 100m but I stopped when I saw everybody stop," he said Gardiner of the Bahamas. "I came back and re-focused and went again."
Montgomery finished the race but was later disqualified.