Niamh Coyne won Ireland's first medal of the Youth Olympics when she claimed silver in the 100m breaststroke.
The Dubliner finished 1.02 seconds behind gold medalist Anastasia Makarova of Russia with Lithuania's Kotryna Teterevkova in third.
It was heartbreak in the race for another Irish swimmer. Mona McSharry from Sligo finished an agonising 0.02 seconds outside the medals in fourth. McSharry had led the field for much of the race.
Earlier in the week, both swimmers missed out on medals in the 50m breaststroke final when McSharry finished fourth and Coyne in fifth.
"I wasn't expecting to medal out here," Coyne told RTÉ about her medal win.
"It's October, a bit of a weird time for swimmers. I was really happy with it. The first 50m I just needed to build and get my turn right. After that, I just had to go for it.
"I couldn't see anyone, even on the turn. I didn't know where I was. I was just like, 'touch the wall, touch the wall and be finished!'.
"I was shocked; shocked and happy. This is in the top one!"
The Youth Olympics, which take place every four years, are being held in Buenos Aires. A team of 16 Irish competitors is taking part in the third edition of the Games.
You can watch the 100m breaststroke final below.