- Tirunesh Dibaba wins first track gold of the London Olympics
- Dibaba successfully defends her 10,000m crown
- Tomasz Majewski retains his men's shot put crown for Poland
- Home hope Jessica Ennis leads women's heptathlon after first day
Ethiopian Tirunesh Dibaba made a successful defense of her Olympic 10,000 meters crown to round off the first night of track and field finals Friday.
Dibaba used her famed finishing kick to pull clear of Kenyan pair Sally Kipyego and reigning world champion Vivian Cheruiyot with a 62 second last lap to win in 30 minutes 20.75 seconds.
It was the third Olympic gold medal for Dibaba, who is a seven-time world champion and holds the world record for the 5,000m.
Dibaba's teammate Werknesh Kidane pushed the pace after halfway in the grueling 25-lap event to whittle down the medal contenders to two Ethiopians and two Kenyans.
Kidane paid for her efforts but an ever confident Dibaba hit the front before the bell and victory was a formality with Kipyego claiming the silver.
While Dibaba was doubling up, Poland's Tomasz Majewski became only the second man in history to retain the Olympic shot put title.
The 30-year-old threw 21.89 meters to edge out Germany's world champion David Storl, who had a best of 21.86m.
Reese Hoffa of the United States took bronze with 21.23m.
Majewski matched the feat of American Parry O'Brien, who won successive golds in 1952 and 1956.
The Pole took the lead in the third round and finished off in style with his best effort.
Earlier, the home crowd in an 80,000 seater Olympic Stadium with few empty seats, had reason to cheer as Jessica Ennis took a commanding lead in the women's heptathlon.
Ennis, the poster girl of the 2012 London Games, set personal bests in the 100m hurdles and 200m on the way to a first day score of 4,158 points, 184 clear of Lithuanian Austra Skujyte.
With the long jump, javelin and 800m to go, Ennis has a healthy lead over defending Olympic champion Natallia Dobrynska of Ukraine and Russian world champion Tatyana Chernova, who were 10th and ninth respectively.
Britain's Christine Ohuruogu made a successful start to her defense of the women's 400m title with a 50.80 seconds clocking to come through in the first round.
Her old rival Sanya Richards-Ross of the United States also progressed. Amantle Montsho of Botswana was fastest qualifier in 50.40 seconds.
Saturday's track and field action will see the first appearance for Jamaica's sprinting superstar Usain Bolt as he begins the defense of the 100m title.