Updated

On a day that could feature the last individual medal of Michael Phelps' Olympic career, Jessica Hardy of the United States qualified for the semifinals of the women's 50-meter freestyle in the morning session at the Aquatics Centre.

Phelps is in the 100m butterfly final Friday evening and will aim for his third straight gold in the event. On Thursday night, the American swimming star earned his 20th overall Olympic medal and 16th gold, extending both records. He posted the fastest time in qualifying for the 100 fly on Thursday, just minuites after beating teammate Ryan Lochte for gold in the 200 individual medley.

The 27-year-old Phelps, who swears the London Games will be his last Olympics, has medaled in each of his races since finishing fourth in the 400 IM Saturday night, the race Lochte won in their first matchup against each other here. Phelps has two gold and two silver medals in London.

Phelps should have stiff competition for gold this evening, as the 100 fly is the race he won famously by .01 seconds with a half-stroke at the end over Serbia's Milorad Cavic at the Beijing Olympics four years ago.

Cavic also qualified. As did Chad le Clos, the 20-year-old South African who idolizes Phelps and beat him in the 200 fly here -- Phelps' signature race. None of the other swimmers are expecting to beat Phelps in his last individual race in his last Olympics.

But, before Phelps gets another shot at gold on Friday night, the Aquatics Centre hosted several heats in the morning. Hardy kicked the day off by posting the 12th-best time in the 50 free and will race in the semifinals of the event on Friday night. Kara Lynn Joyce of the U.S. missed qualifying after losing a swim-off to Great Britain's Amy Smith.

The Netherlands had the top two qualifying times in the 50 free thanks to Ranomi Kromowidjojo and Marleen Veldhuis.

Meanwhile, the U.S. men qualified with the top time in the men's 400m medley relay. The team consisted of Nick Thoman, Eric Shanteau, Tyler McGill and Cullen Jones, but Phelps will almost certainly compete in the final on Saturday along with Nathan Adrian, winner of 100 freestyle gold in London. Recently crowned 100 backstroke champion Matt Grevers could also be included on the final team.

The U.S. women also qualified for the final of the 400 medley relay, recording the fourth-fastest time. Hardy also swam in that event along with Rachel Bootsma, Breeja Larson and Claire Donahue. The Australian team, which included Emily Seebohm, the silver medalist in the 100 backstroke, posted the best time, finishing 3.46 seconds ahead of the Americans.

Sun Yang logged the best time in heats for the men's 1500 free, finishing the distance race in 14 minutes, 43.25 seconds. Canada's Ryan Cochrane was 6.06 seconds behind in the third position while American swimmer Connor Jaeger moved onto Saturday's final with the seventh-best time.

Andrew Gemmell of the U.S. just missed qualifying for the 1500 final, finishing ninth.