The 18-year-old, who won four golds at last year’s World Junior Championships, was inside American legend Michael Phelps's nine-year-old world record at the half-way stage.

He faded in the last 50m but his time of 1 min 52.79sec was further evidence that he has eclipsed his team-mate Laszlo Cseh, a six-time Olympic medallist and the oldest man at these Championships at 32.

Cseh did not make the final but Hungary still had a one-two finish with 21-year-old Tamás Kenderesi second in 1:54.36.

Third place went to Italy's 16-year-old Alessandro Burdisso, who came in as a reserve when Great Britain’s James Guy withdrew to focus on the next event, the men’s 4x200m freestyle relay, which started seven minutes later.

"It's amazing - I am very lucky," said Burdisso, one of five Italian medallists on a night of six finals.

Guy and his British team-mates, including 18-year-old Tom Dean, won the freestyle relay with a time of 7:05.32.

Russia finished second in 7:06.66, while Italy came third in 7:07.58.

The third teenage gold medallist of the evening was Alessandro Miressi, who held off home favourite Duncan Scott and France’s Mehdy Metella in a tight finish to the men's 100m freestyle.

Miressi, 19, is a former European junior champion at the distance.

He clocked a time of 48.01 to beat Scott by a margin of 0.22 seconds.

Metella finished a further 0.01 seconds back in third.

Germany’s Florian Wellbrock was a surprise winner of the men's 1,500m, which saw Italian favourite Gregorio Paltrinieri finish only third in 14:42.85, having felt unwell before the race.

It was Paltrinieri's first defeat over the distance since the 2013 World Championships.

Wellbrock improved his semi-final time by nearly 20 seconds, prevailing in 14:36.15.

"Today I didn't focus on my times," he said.

"It was much more a race swum in the head rather than with the arms."

Ukraine’s Mykhailo Romanchuk took the silver medal in 14:36.88.

Also tasting victory today were Britain’s Georgia Davies and Russia’s Yuliya Efimova, the winners of the women’s 50m backstroke and 100m breaststroke events respectively.

Davies triumphed in a time of 27.23, which was just 0.02 seconds slower than the European record she set in the heats yesterday. 

Russia's Anastasia Fesikova finished second in 27.31, while Finland's Mimosa Jallow came third in 27.70.

Efimova, meanwhile, set a Championship record of 1:05.53 to secure her gold medal.

It bettered the previous mark, which she set herself yesterday, by 0.24 seconds.

Lithuania's Rūta Meilutytė clinched the silver medal in 1:06.26.

Italy's Arianna Castiglioni completed the top three in 1:06.54.

Swimming action at Glasgow 2018 is due to continue tomorrow with a further six finals scheduled.