The 22-year-old from Edinburgh accelerated off the final bend to stun a world-class field, holding off a late charge by Kenyan world silver medallist Elijah Manangoi to shatter his personal best with a time of 3:34.17.
“I’m just stunned by that,” said Wightman who became the first European male ever to win a Diamond League race at the distance. “When the leaders were still within reach with 250 to go, I thought: ‘there’s a chance here, let’s not blow it’. My finishing has been pretty strong this season so far, so when I got to the front with 100 metres left, I didn’t feel I’d shot my bolt. I was just running for my life at the end. I had no idea what was happening behind me. But it was amazing to get that win. That definitely beats anything I’ve done before.”
The former European junior champion, who will run for GB&NI at next week’s European Team Championships, moves into third spot in the all-time Scottish charts behind John Robson and Graham Williamson – and above Mo Farah into top spot in this season’s UK rankings.
Lynsey Sharp dipped under the world championship qualifying mark for the first time this season in the 800 metres. But the Scot was only eighth in 2:00.41 as Olympic gold medallist Caster Semenya kept her unbeaten streak intact.
CJ Ujah was second to Andre deGrasse in the 100 metres.