Olympic champion and world record-holder Karsten Warholm laid down a huge marker of his ambition to regain the 400m hurdles title at the World Athletics Championships in Budapest when he set a Diamond League record of 46.51 in Monaco on July 21.

The 27-year-old Norwegian said before his race that his experience at last year’s World Championships in Oregon, where he finished seventh after recovering from a hamstring injury incurred in his opening meeting of the season, has been a strong motivating factor this year.

"It was really nice to do this again – that 0.01 off the Diamond League record and also the track record," Warholm said after a performance that also bettered his own top world mark for 2023.

"This is a nice timing as the World Championships is just around the corner. Since I was injured last year, I enjoyed the racing more."

In his wake was Brazilian Alison dos Santos, who took over the world title he had won in 2017 and 2019, who clocked a season’s best of 47.66.

Dos Santos, who finished third in the Tokyo Olympic final, has had to recover from a serious injury early this year in the form of a torn meniscus in his right knee which required surgery.

At the time it appeared his season was over before it had started, but he returned to top class action at the Silesia Diamond League meeting on 16 July, where he finished third in the 400m in 44.73. And in his first race over the hurdles in Monaco the 23-year-old from Sao Paulo did enough to stir his World Championships ambitions.

"That was the perfect opportunity for me to come back to run,” he said. "Now I will get ready for Budapest, to be able to win my world title again."

But Warholm and Dos Santos are not the only ones with world gold in their sights, as Rai Benjamin is equally determined to make a breakthrough in Budapest.

The 26-year-old US athlete took silver behind Warholm at the Doha 2019 World Championships and bettered the Norwegian’s world record of 46.70 in the Tokyo Olympic final where he clocked 46.17 and took another silver as Warholm reached deeper to set the current world record of 45.94.

Last year, with Warholm still a way off full fitness following a hamstring strain after clearing the first hurdle of his first race of 2022 at the Rabat Diamond League meeting, Benjamin must have thought his chance had come to make a golden impression on his home track in Eugene, Oregon – but Dos Santos won with a South American record of 46.29, with the home runner clocking 46.89.

How close can the Brazilian get to his best form in the time available? At the moment his is only fifth fastest in this season’s list, with two other runners above him – Kyron McMaster of the British Virgin Islands, the double Commonwealth champion and fourth-place finisher in Tokyo, who has clocked 47.26, and CJ Allen of the United States, who has set a personal best of 47.58.

Others likely to make their mark include France’s Ludvy Vaillant, who has run a personal best of 47.85 this season, as has Jamaica’s Roshawn Clarke, and 31-year-old Rasmus Magi of Estonia, European silver medallist in 2014, who has run 48.04 this season.

Italy’s 24-year-old 2018 world U20 champion Alessandro Sibilio, a Tokyo Olympic Games finalist, is also one to look out for.