Thiam’s victorious total of 6810 points was built on a flurry of personal bests – and launching a javelin with a ruptured elbow ligament – as she survived a stern examination in the 800m to triumph.
Ennis-Hill had needed to overturn a 10-second deficit in the concluding event, but was unable to break her 21-year-old rival despite claiming a commanding win to finish on 6775 points.
Nafissatou Thiam (BEL) of Belgium celebrates winning the gold medal
Image credit: Reuters
Canada’s Brianne Thieson-Eaton (6653 points) secured the bronze medal, with Katarina Johnson-Thompson’s hopes fading after a miserable javelin competition earlier on Saturday.
Ennis-Hill hinted afterwards that the competition may be her last.
100M HURDLES
Ennis-Hill’s time of 12.84 seconds – equating to 1,149 points – was well clear of expected rivals Theisen-Eaton (13.18s) and Johnson-Thompson (13.48s) in arguably her strongest event.
Despite the damp conditions leading to cautious runs from her competitors, Ennis-Hill stormed to victory in the final heat to eclipse her opening time from the IAAF World Championships in Beijing by 0.07s.
Ennis-Hill in action on first day of athletics
Image credit: Reuters
Barbados’ Akela Jones and Netherlands’ Nadine Visser took second and third respectively, although both were outside 13 seconds.
Johnson-Thompson was second in heat three of four, only nine-hundredths short of her personal best, while Thiam started with a 13.56s in heat two (1041 points).
HIGH JUMP
An extraordinary high jump competition saw the three pre-event contenders shine, with Thieson-Eaton recovering from an early scare to post 1.86m, Ennis-Hill setting 1.89m (1093 points) and Johnson-Thompson soaring to new heights.
A remarkable head-to-head between Johnson-Thompson and Thiam saw them propel each other to a new Olympic Best in the heptathlon, with them both eventually bowing out at 1.98m (1211 points) after three failures at 2.01m.
A feat that saw Johnson-Thompson assume the lead.
Britain's Katarina Johnson-Thompson reacts in the Women's Heptathlon High Jump during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 12, 2016.
Image credit: AFP
SHOT
Johnson-Thompson’s technique deserted her as she relinquished her grasp in the lead, failing to hit the 12m line as she slumped to sixth.
Ennis-Hill was equally gutted with a throw of 13.86m (785 points) as Thiam climbed into the overall lead with a competition-best throw of 14.91m (855 points).
Belgium's Nafissatou Thiam competes in the Women's Heptathlon Shot Put during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 12, 2016.
Image credit: AFP
200M
Johnson-Thompson bounced back to post the quickest 200m – 23.26s – to finish the opening day in fourth, 100 points off the pace.
Meanwhile, Ennis-Hill went into the overnight break with a 75-point lead on Thiam after posting 23.49s (1030 points). Her Belgian rival, in one of her weaker events, clocked 25.10 seconds (878 points).
Britain's Katarina Johnson-Thompson competes in the Women's Heptathlon 200m during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 12, 2016
Image credit: AFP
LONG JUMP
Thiam emerged as a serious gold medal threat with a leading leap of 6.58m (1033 points), with Ennis-Hill staying in contention with a jump of 6.34m (956 points).
It was the event that haunted Johnson-Thompson at the World Championships in Beijing, where her competition imploded with three foul jumps, and she was unable to hit her maximum as she went out to 6.51m.
JAVELIN
Ennis-Hill sent her opening throw beyond 45m (784 points), sparking debate that it could be a gold-winning throw.
But with a ruptured tendon and heavily-strapped elbow, Thiam launched a monster effort out to 53.13m (921 points) to leave her with a huge advantage going into the final event.
Johnson-Thompson cut a frustrated figure, arching her javelin high into the Brazilian sky and resorting to practicing her technique with a water bottle, as her podium challenge ended.
Nafissatou Thiam (BEL) of Belgium competes
Image credit: Reuters
800M
Ennis-Hill set out her intentions early, hitting the front from the gun, but Thiam set her sights on her chief rival and refused to let the gap grow too great.
The Brit posted 2:09.07 (978 points), while Thiam finished in 2:16.54 (871 points) – a result that ensured the youngster went away with a fine gold medal.
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