Diogo Ribeiro executed a perfectly-timed finish to win the 50m butterfly and become Portugal’s first world champion in Doha.
The 19-year-old won his country’s first medal in the pool with silver in the one-length event at the 2023 World Championships in Fukuoka.
While he didn’t have the best of starts in Monday’s final, Ribeiro made his way through the field and powered into the wall to take gold in 22.97secs.
On leaving the pool, he absorbed the history of the moment and revealed the prospect of becoming world champion had left him unable to sleep.
“When I touched the wall and watched the time and I saw I was first, I got a feeling that I had never ever felt before,” he said.
“This medal goes for my country, my staff, my family, my girlfriend who’s here supporting me… it means that we all can do it, we just have to think big and always think that everything is possible.
“I can’t believe that I’m a world champion and that the national anthem of Portugal will sound for me, for the first time ever!”
It was the second gold of the night for Europe after Angelina Kohler had claimed an emotional title in the women’s 100m butterfly.
The German led throughout to take the gold in 56.28, the emotion pouring forth once she had seen the scoreboard.
It was the 23-year-old’s first senior medal, a day after she lowered the national record to 56.11.
“It will take some time until I realise what I have just achieved for German swimming,” she said.
“It means so much that my head just cannot take it, I am speechless.”
Louise Hansson of Sweden made it two Europeans on the podium with bronze in 56.94.
The fastest second 50m of the entire field propelled Nicolo Martinenghi from fifth to second in the men’s 100m breaststroke.
The Italian touched in 58.84 for his second straight world silver with Adam Peaty third in 59.10 at his first long-course World Championships since Gwangju 2019.
Danys Rapsys of Lithuania led the way in the men’s 200m freestyle semifinals with Germany’s Lukas Martens third through as four European men progressed to Tuesday’s final.
Mona McSharry of Ireland was second into the women’s 100m breaststroke final and will be joined by Tes Schouten of the Netherlands and Lithuanian Kotryna Teterevkova.
Benedetta Pilato missed out in ninth, two years after winning the title, while reigning champion Ruta Meilutyte failed to negotiate the prelims.
Hugo Gonzalez of Spain was the fastest of five European men into the 100m backstroke final while two British and two Dutch made progressed in the women’s race.
Hungary, Spain and Greece all triumphed in the women’s water polo quarterfinals to make it through to the medal round.
Hungary beat defending champions Netherlands 13-12 in a penalty shootout after the match was tied at 8-8, a result that booked an Olympic berth.
Rita Keszthelyi scored three goals and the first of the shootout for Hungary but victory hinged on Alda Magyari’s save for 5-4.
Lieke Rogge and Lola Moolhuijzen scored two apiece for the Dutch while Laura Aarts finished with 15 saves.
Eirini Minou scored five as Greece beat Italy 14-11 while Judith Forca was also on target on five occasions as Spain downed Canada 12-9.