Ciara Mageean smashes the Irish record in thrilling 1500m Diamond League win

Mageean, who took silver behind Muir at both the Commonwealth Games and European Championships, took almost four seconds off her personal best as she clocked a time of three minutes 56.63 seconds.

And the 30-year-old from County Down, who had never run under four minutes previously, also sliced more than two seconds off the Irish record of 3:58.85 set by Sonia O’Sullivan in Monaco in 1995.

Muir battled hard down the home straight to take second ahead of Ethiopia’s Freweyni Hailu.

A delighted Mageean said: “I expected to run fast and I actually had the national record on my mind. I thought that I had it in me to beat that record and maybe run 3.57.

“However, before this race I never ran under four minutes so to run a time of 3.56.63 is something that blows my mind.

“People say that in athletics and in life every so often you have a day where you are completely in the zone. It doesn’t happen when you want to and you never know when it will happen. I can only say that this is how I felt today; I was in the zone and it felt like I was running on clouds.

“I’m so happy with this result and to be able to beat the national record of a legend like Sonia O’Sullivan is so special.

“For me winning a medal at a major championship is still the most important thing, but breaking a record is also something you want as an athlete. I can’t wait to celebrate this with my team and my family.”

In the final track event of the evening, Britain’s Jake Wightman stormed to victory in the 800 metres, setting a new Scottish record and taking the scalp of world champion Emmanuel Korir.

Wightman, who won gold over 1,500m in Eugene while Korir triumphed over 800m, set a new personal best of 1:43.65 as he finished comfortably ahead of Algeria’s Djamel Sedjati, with Korir forced to settle for third.

“I wanted to run under 1:43.88, which is the Scottish record, and I did,” Wightman said. “To win a race in a field like this, I’m really pleased with that.

“In Zurich, I’m running the 800m as well and then a road mile in New York to finish off this long season. After that I’m taking a week or three off to spend some time with friends and family.

“It has been one championship after the other so I’m very much looking forward to take some time and reflect on this amazing season.”