The track and field competition at the London Games kicked off Friday at Olympic Stadium and the first two gold medals went to a pair of familiar faces.

Tirunesh Dibaba won the women's 10,000 meters for a second straight Olympics and Poland's Tomasz Majewski also repeated as champion in the men's shot put.

Dibaba won her third Olympic gold medal, easily defending her 10,000m title from four years ago in Beijing. She became the second woman to repeat in the event, joining fellow Ethiopian Derartu Tulu, who won the 10,000 at both the 1992 and 2000 Summer Games. Dibaba is the first to win the event at consecutive Olympics.

"It's very special," said Dibaba. "I have worked very hard for this. No one has ever done what I did today."

The distance race closed out the first day of track and field action at Olympic Stadium and Dibaba ended the night in style.

The winner of both the 5,000 and 10,000 four years ago in Beijing, the four- time Olympic medalist kicked into high gear with over a lap to go and completed the race in 30 minutes, 20.75 seconds -- 5.62 seconds before Kenyan Sally Jepkosgei Kipyego crossed the finish line.

Kipyego's compatriot Vivian Jepkemoi Cheruiyot won bronze with a time of 30:30.44.

Ethiopians Werknesh Kidane and Beleynesh Oljira helped set the pace for Dibaba and finished fourth and fifth, respectively. Amy Hastings had the best time of three Americans in the race but finished in 11th place, 49.94 seconds behind Dibaba.

Majewski defended his Olympic title from the 2008 Beijing Games with a throw of 21.89 meters to beat Germany's David Storl by just .03 meters.

Majewski became only the second man to win the men's shot put at consecutive games. The only other person to repeat in the event was Parry O'Brien of the United States, achieving the feat at the 1952 and '56 Summer Games.

American thrower Reese Hoffa, who finished seventh in Beijing, took third with a toss of 21.23 meters.

"The experience here in London is incredible," said Hoffa. "I am sure a lot people can't wait to see the medal."

It was the first Olympic medal for Hoffa and the 48th all-time shot put medal for the U.S. The Soviet Union is next on that list with five.

Hoffa's countryman Christian Cantwell, the silver medalist in Beijing, was fourth with a top throw of 21.19 meters. Canada's Dylan Armstrong finished fifth and Ryan Whiting of the U.S. came in ninth.

Round 1 of the women's 100m also began Friday evening with seven heats and all the favorites moved onto the semifinals. Carmelita Jeter, winner of the event at the U.S. Olympic Trials, posted the fastest time with a run of 10.83 seconds, while defending gold medalist Shelly-Ann Fraser-Pryce of Jamaica was seventh. Americans Allyson Felix and Tianna Madison and Jamaica's Veronica Campbell-Brown and Kerron Stewart also moved onto the semis.

The Jamaicans swept the 100 in Beijing, with Sherone Simpson and Stewart taking silver and bronze, respectively, behind Fraser-Pryce. The semis and finals will take place on Saturday night.

Four of the seven events in the heptathlon were staged on Friday and Jessica Ennis of Great Britain is in the lead with 4,158 points. Lithuania's Austra Skujyte is next with 3,974 points and Canada's Jessica Zelinka is third at 3,903.

Hyleas Fountain of the U.S., silver medalist in Beijing, is currently sitting in fifth place and is 258 points behind Ennis.

Heptathlon gold will be award Saturday after athletes compete in the long jump, javelin and 800m race.

Friday's track and field action also included qualifying for the men's 1,500m and long jump as well as the women's discus. The finals in both the long jump and discus will be contested on Saturday.

In the morning session at Olympic Stadium, Beijing bronze medalist Sanya Richards-Ross' moved into the semifinals of the women's 400-meter race along with fellow Americans Francena McCorory and DeeDee Trotter. Great Britain's Christine Ohuruogu, the 2008 gold medalist also moved and Amantle Montsho of Botswana had the fastest time with a run of 50.40 seconds, 1.38 ticks faster than Richards-Ross, who placed 12th.

Also on Friday morning, Angelo Taylor, Kerron Clement and Michael Tinsley of the U.S. all moved into the semifinals of the men's 400m hurdles. Taylor won gold in Beijing and Clement claimed silver.