Laura Trott crushed the opposition to retain her women's track cycling omnium title and become the first British woman to win four Olympic gold medals on Tuesday.

With the victory, the 24-year-old clinched her second successive team pursuit and omnium double after she also won both events at London in 2012.

"I can't believe it, I did not expect that at all. I'm just so happy," Trott told the BBC. "It has all come together -- what a day. I'm literally over the moon.

"It's down also to the backroom team who have put up with me being stroppy at times.

"To be able to repeat my London success -- I just can't explain what I'm feeling right now."

America's two-time omnium world champion Sarah Hammer took silver for the second time in a row with Jolien d'Hoore of Belgium rounding off the podium.

Hammer has won a silver medal in all four of Trott's golden triumphs.

Trott, also the world champion, came into the last of the event's six disciplines with a commanding lead of 24 points after coming first in three of the previous races.

She seemed to be simply enjoying herself during the final points race, extending her lead as Hammer and d'Hoore battled behind her.