Olympic champion Ruta Meilutyte won the women's 100m breaststroke gold medal on Tuesday, a day after setting the world record, as teenagers led the way at the world aquatics championships.

The 16-year-old Lithuanian set the world record of 1 min, 04.35 sec in Monday's 100m breaststroke semifinals before fellow 16-year-old Katie Ledecky of the US smashed the 1,500m freestyle record on Tuesday in Barcelona.

In the women's 100m breaststroke final later on Tuesday, Meilutyte won gold after clocking 1 min, 04.42 sec, just seven hundredths of a second outside her own day-old record.

Russia's Yuliya Efimova claimed silver at 0.60 sec back with Jessica Hardy of the US 1.10 adrift for bronze.

With 18-year-old Missy Franklin having claimed two of the eight gold medals she is bidding for, teenagers are setting the pace in Barcelona, said Meilutyte.

"I think it is great that young people are stepping up," she said, having won the Olympic title in London as a 15-year-old.

"A lot of it goes down to amazing older swimmers inspiring us to do these things and achieving our dreams.

"It is something I always wanted to do and to represent my country."

Meilutyte said she has learnt how to cope with the pressure of racing at a major event in the wake of her London triumph.

"I got a bit more experience from the Olympics, so that makes things easier and just being in the atmosphere, but I still have lots of things to learn," she said.

"I think I am a bit more calm and had more confidence in myself since the Olympics.

"Pressure doesn't really bother me to be honest, I could feel a lot of people watching me, but I just went out there and did my best."

Having now added the world title to her Olympic crown, Meilutyte said she had looked to improve on the world record in Tuesday's final before fatigue set in.

"I was think about improving the time, but maybe the excitement and the adrenalin meant I rushed my stroke a little bit," she said.

"I was dying towards the end, but I am really happy with the time, because it is nearly the same as last night.

"There are still things to improve which is great, I'm really happy with the time and the medal which is good.

Bronze medalist Hardy, whose four-year-old mark Meilutyte broke, expressed no regrets at watching her record fall.

"To watch her break my record last night was really fun," said the 26-year-old Hardy, who set the previous world record of 1 min, 04.45 in August 2009.

"She is an awesome competitor and to race someone who is so good and so kind is great.

"I almost quit the event in the last couple of years, so it is really fun to swim so fast and race such a great field.

"Swimming happy is the best way to swim, I went through a period when it was not fun and not happy.

"So to come back swimming fast, swimming effortlessly and enjoying it is the best thing I could ask for," she said after the showdown.