British heptathlon star Jessica Ennis-Hill made a smooth start to the defence of her Olympic crown Friday, sitting in third place after the opening two events of the gruelling discipline.

Ennis-Hill landed an early psychological blow on Canada's Brianne Theisen-Eaton with an impressive 100m hurdles victory. 

In blustery, overcast conditions, Ennis-Hill produced a blemish-free performance to win her race in 12.84sec at the near-empty Rio Olympic Stadium. It was her third fastest time since winning in London.

The 30-year-old darling of British track and field, who became a mother last year, is bidding to become only the third woman to retain an Olympic athletics title after giving birth.

Hurdler Shirley Strickland achieved the feat in 1952 and 1956 before triple jumper Francoise Mbango Etone emulated it with victories in 2004 and 2008.

Theisen-Eaton, who took silver behind Ennis-Hill at last year's World Championships in Beijing, was left trailing in the Briton's wake, finishing in sixth place.

Ennis-Hill's run earned her 1,149 points, putting her into the early lead of the seven-discipline event.

Akela Jones of Barbados was just behind after clocking 13sec for 1,124pts.

However, Ennis-Hill saw her lead whittled away in the high jump despite landing a season's best of 1.89m, the highest she has jumped since the London Games.

Belgium's Nafi Thiam and Briton Katarina Johnson-Thompson both cleared a world heptathlon best of 1.98m.

Johnson-Thompson's effort saw her take the lead on 2,264 points, with Thiam in second (2,252) and Ennis-Hill third (2,242).

Theisen-Eaton's time of 13.18sec in the hurdles and 1.86m in the high jump left her in fifth place overall behind Barbadian Jones.

Source: AFP