The British women won the European 4x100m freestyle relay title for the first time in 94 years with a stunning victory on the opening night of swimming in Budapest.
The quartet of Lucy Hope, Anna Hopkin, Abbie Wood and Freya Anderson won in a British record of three minutes 34.17 seconds.
They held off the challenge of the Netherlands to claim gold.
“To win my first senior medal and set a new record is just amazing,” Wood said.
Britain claimed silver in the men’s 4x100m free relay, while Aimee Willmott was second in the 400m individual medley final.
Russia’s Kliment Kolesnikov lowered his own world record to 23.93 secs in the 50m backstroke semi-finals.
The British women’s victory, which was their first since the 1927 Europeans is likely to secure them a place in the event at the Tokyo 2020 and as it was achieved within the Olympic consideration time, it is highly likely British Swimming accept the berth and field a women’s 4x100m free line-up in Japan.
“I love the extra pressure and hopefully we’ve made the selectors happy,” Anderson said.
Hopkin added: “I don’t think we expected gold, but it’s an amazing feeling.”
Tom Dean, Matt Richards, James Guy and Duncan Scott finished second to Russia, but it secured Britain a first European medal in the men’s 4x100m freestyle relay since 1962.
Their time of 3:11.56, knocked 0.06 secs off the previous British record.
“It’s a new team and we’re not very experienced, but we have some lads who can be really dangerous in this event and we’re only going to get stronger and stronger,” Guy told BBC Sport.
English Commonwealth champion Willmott last won a European medal in 2014, but the swimmer, who considered retirement after the postponement of the Tokyo Olympics, was rewarded for her perseverance.
The 28-year-old finished in four minutes 36.81 seconds, to tie for second with Viktoria Mihalyvari of Hungary, with Olympic champion Katinka Hosszu taking gold in her home pool.
“I’ve had a few disasters at Europeans so it’s really nice to win a medal,” Wilmott told BBC Sport.
“It’s been a difficult year since the Olympics were delayed and I was really struggling in January, but I’ve fought back through the trials and to now be here competing for Great Britain and winning a medal is a bonus as we head towards Tokyo.”
Olympic champion Adam Peaty and world silver medallist James Wilby eased through the 100m breaststroke semi-finals and will return for the final on Tuesday.
Anna Hopkin will also return for the 50m freestyle final.