French swimmer Yannick Agnel has captured his second gold medal in 24 hours, winning the men's 200m freestyle final.
Yang Sun of China and South Korea's Taehwan Park tied for second. US world champion Ryan Lochte came fourth, missing out on a medal by 0.09 of a second.
The previous evening Agnel swam a remarkable final leg to seize the men's 4x100 metres freestyle relay gold medal for France, Reuters reports.
In the men's 100m backstroke, Matthew Grevers won gold for the US with an Olympic record time of 52.16 seconds. Team-mate Nick Thoman took silver and Japan's Ryosuke Irie finished third.
Missy Franklin won another gold for the United States in the women's 100m backstroke.
Australia's Emily Seebohm was disappointed with her second placing after being the favourite to take out the race.
The United States was relegated to second in the 100m women's breaststroke final, with 15-year-old Lithuanian swimmer Ruta Meilutyte surviving the ultimate test of nerves to win the event.
The start of the race had been delayed by a technical malfunction in which the starter's gun go off before he had called "on your marks", Reuters reports.
The young swimmer was unfazed and led throughout the race, despite a strong challenge from the American world champion, Rebecca Soni.
Teen swimming sensation
Teenage Chinese swimmer Ye Shiwen broke a second record at the Games when she posted the fastest qualifying time in the semi-finals of the women's 200m individual medley.
The 16-year-old won the semi-final in an Olympic record time of 2:08.39 on Monday.
Last week, Ye shattered the world record in winning the 400 medley and completed her final lap almost as fast as men's champion Ryan Lochte did when he won in the same event.
Her sensational performance got people talking and prompted her to issue a firm denial that she had cheated.
An IOC official said at a media conference it was a tragedy that as soon as there is an outstanding performance, people start wondering if drugs cheating is involved.
Southland swimmer Natalie Wiegersma, 22, failed to make it out of 200m individual medley heats.
She swam more than four seconds outside her best, with a time of 2:16.24, and placed 26th of the 34 starters.