>> Rio's already seen more than one world record sunk. British swimmer, Adam Peaty, beating his own record Saturday, in the 100-meter breaststroke and that was just the qualifiers. He's bidding for gold in the pool Sunday. And some bad news for his competitors, Peaty says he has more in the tank.
But Australia's already seen a gold rush in the water. The women's 4x100 freestyle relay team winning in style with a world record, it was theirs to break. Mack Horton in the men's 400 meter freestyle taking their gold count to two and helping to send Australia top of the medal table after the first competitive day.
The United States ending it sitting in third, but their teenage sensation, Virginia Thrasher, took aim at the 10-meter air rifle Saturday, the 19-year-old's gold, the very first to be won in Rio. But Team USA also took a hit in the opening day's proceedings, Venus Williams crashing out of the women's tennis singles in the first round.
Her hopes of winning her fifth Olympic gold now lie in the women's doubles.