Crouser's fellow American, who threw 22.91m to beat him to the world title in Doha last year by one centimetre in a epic final, was second with a best of 21.30m.

The men's shot put was taking place in the city's Fountains Park as a precursor to tomorrow's main programme of events at the Sportpark Mladost, where home favourite Sandra Perkovic, discus champion at the 2012 and 2016 Olympics, will return to one of her favoured hunting grounds in what will be her first competition since March 7.

Crouser, who has established a stunning series of throws over 22 metres this season as he targets the world record of 23.12m set by his American compatriot Randy Barnes, maintained his high level in his latest competition to achieve the best mark in Europe since August 23, 1988, when Werner Gunthor threw 22.75m in Bern.

Four of his six efforts went further than 22 metres as his sequence read: 21.03, 22.10, 22.74, foul, 22.59 and 22.31.

The Olympic champion from Portland, Oregon has now won all of his nine competitions since that Doha final, including the Millrose Games in New York in February where he beat Kovacs with a throw of 22.19m compared to his rival's 21.34m.

Before the competition, Kovacs had commented: "This was usually my last meeting of the season and now it’s the first one.

"I would be very happy if I could repeat my result from last year (21.20m)."

In her last competitive event, Perkovic, who salvaged world bronze from an injury-ravaged season last year, won the Croatian Winter Throwing Championships with an effort of 65.93 metres – the second best recorded this year behind Valarie Allman of the United States, who reached 70.15m on August 1.

She faces Melina Robert-Michon of France, whose best throw of the season, 64.14m, came back in February and puts her sixth on the 2020 world listings.

Croatia’s current pandemic restrictions on public gatherings will prohibit spectators gathering at the shot put competition, but 700 will be allowed to watch the main programme.

Sweden’s world champion Daniel Stahl will be seeking to return to the gold standard after seeing his run of 15 consecutive victories ended in Berlin on Sunday by the 2017 world champion Andrius Gudzius.

The Lithuanian threw 66.72 metres, with Stahl’s best being 65.89m.

The men’s 110 metres hurdles is the signature event of a meeting named in honour of Croatia's inter-war hurdles favourite Boris Hanzekovic.

Wilhem Belocian of France is the fastest of the entrants this year having clocked a career best of 13.18sec in the opening Wanda Diamond League meeting of the season in Monaco on August 14.

Freddie Crittenden, the 2019 Pan-American Games silver medallist who has clocked 13.30 this season, is also in the field.

The women's high hurdles field includes Cindi Ofili of Britain and Payton Chadwick of the United States, who have clocked 12.88 and 12.97 respectively this season.

In the men's 800m, Britain’s Jake Wightman, Andreas Kramer of Sweden and Amel Tuka of Bosnia and Herzegovina play it again after their hugely competitive race in Ostrava last week in which winner Wightman and runner-up Kramer improved their lifetime bests to 1 minute 44.18sec and 1:44.47 respectively.

Tuka, the 2017 world bronze medallist, was third in 1:44.51.

In the high jump, Yuliya Levchenko of Ukraine, one of the season's two two-metre jumpers, will take on Australia’s rising star Nicole McDermott, who has improved to 1.98 metres this year.