The 22-year-old from Camageuy, winner of the 2018 world indoor title as an 18-year-old, appeared poised to win through his third-round effort of 8.41 metres.

But then Tentoglou, leader of this year’s world rankings with 8.60m, exactly equalled that mark and took over gold medal position through having a superior second-best jump - with 8.15m trumping 8.09m.

Faced suddenly with the need to outdo himself, Echevarria mistimed his run-up and fouled out, setting for silver ahead of compatriot Maykel Masso, who jumped 8.21m.

"What an incredible competition," said Tentoglou.

"What an incredible jump, the last jump.

"I wasn't able to get it right at the start.

"But in the end I managed to pull something out to get the medal.

"I managed to jump 8.41m and it was enough - I am very lucky."

Echevarria commented: "It’s not what I expected, the result I expected, but still, it’s a very welcome prize."

The second final of the morning session here, in the women’s 100 metres hurdles, was more predictable as Jasmine Camacho-Quinn of Puerto Rico, the fastest qualifier in an Olympic record of 12.26sec, duly followed through with victory in 12.37.

The 24-year-old thus became the second Puerto Rican to win an Olympic gold following the victory at Rio 2016 of tennis player Monica Puig.

After an agonising wait for a photo-finish, second place went to Kendra Harrison of the United States, who set the world record of 12.20 in 2016, as she was credited with a time of 12.52, with Jamaica's Megan Tapper taking bronze in 12.55.

As she watched a replay of her final, Camacho-Quinn, who is Florida-based and eligible for Puerto Rico through her mother’s nationality, commented: "At this point I was really running for the world record.

"I hit the hurdle, but everything happens for a reason.

"I came through with the gold."

Asked to assess the impact of her gold in her home nation, she replied: "I am pretty sure everybody is excited.

"For such a small country it gives little people hope.

"I am just glad I am the person to do that.

"I am really happy right now."

Camacho-Quinn, whose brother Robert Quinn plays as an outside linebacker for the National Football League team Chicago Bears, went on to thank the man who has guided her since February 2020, John Coghlan.

"My coach came all the way from Ireland just to coach me," she said.

"I really do appreciate that.

"It's been a roller-coaster since I became a professional."

Earlier in the day Sifan Hassan of The Netherlands, who announced yesterday that she intended to seek a 1500m/5,000m/10,000m triple in Tokyo, almost came to grief at the first of those distances.

She was tripped in her 1500m heat and had to make up more than 30 metres to get back with the leading group before acceleration over the final 150 metres to win in 4min 05.17sec.

Hassan now has less than 12 hours to recover for the evening session’s 5000m final.

After that Hassan will be due to face two more rounds of the 1500m.

There is also a 10,000m final where she will be awaited by Ethiopia's world record holder Letesenbet Gidey.

The 18-year-old Christine Mboma of Namibia was the fastest qualifier from the women’s 200m heats, clocking 22.11, a world under-20 record.

Mboma and her fellow 18-year-old Namibian Beatrice Masilingi, who had qualified earlier in what was a then national record of 22.63, have switched events to the shorter sprint after this month’s ruling by World Athletics that they are precluded from events between 400m and 1500m metres because of naturally elevated testosterone levels.

Defending champion Elaine Thompson-Herah, winner of second successive Olympic 100m title on Saturday (July 31), went through in third place from the sixth heat, clocking 22.86.