By Owen Gibson in Beijing/theguardian.com

It was, by any measure, the mother of all comebacks. Just 13 months after giving birth and three years after her last major championships, Jessica Ennis-Hill is once again world champion.
Before heading to Beijing, Ennis-Hill said that winning gold in the Bird’s Nest would equal her achievement in becoming Olympic champion in London on Super Saturday.
And her achievement in triumphing with a total of 6,669 points following consistently impressive results in the long jump, javelin and 800m on Day Two of the championships was in some ways even more remarkable than that era-defining exercise in managing pressure.
Then, she had blown away the opposition with a nerveless hurdles on the opening morning of the Games that left her cruising to victory. This was instead an exercise in consistency, concentration and a victory for the intense training she had put in with her coach Toni Minichiello since returning in earnest last November.
Typically, despite the equivalent of a six-second head start over her nearest rival going into the race, Nadine Broersen of the Netherlands, she powered down the home straight of her 800m race to win in 2.10.13 before collapsing to the floor in delight and relief.
For once she had travelled to a major championships not expecting to win gold and overnight Katarina Johnson-Thompson, the Liverpudlian young pretender to Ennis-Hill’s enduring quality, had been snapping at her heels.
But by the time newspapers outlining the prospect of a British 1-2 had hit the doormats, Johnson-Thompson had seen her chances of a medal snatched away.
She began the day 80 points behind Ennis-Hill with by far her strongest event, the long jump, to come. But disaster struck for the bubbly 22-year-old when she recorded three no jumps and threw away her chance of a medal.
With the pressure on following two fouls, she appeared to soar way beyond the 6.90 mark but after an interminable wait a red flag was raised and replays showed her foot was almost imperceptibly over the line.
The drama didn’t end there after British Athletics submitted an appeal that was ultimately withdrawn over an hour later when all concerned belatedly accepted it was a foul.
“The first one was unfortunate. I hate getting a no jump on the first round because that always puts you in the back foot,” said Johnson-Thompson, from Liverpool.
“The second one was meant to be a safe one, but unfortunately that was a no jump as well. At that point, it was all or nothing for me. I had to give it my all. It was just a very slightly margin, but that’s what it is in athletics, I guess.”
While Johnson-Thompson had recovered from a shaky start in the high jump on the opening day, this time there was to be no shot at redemption. In an instant, the contest turned.
In contrast, Ennis-Hill had used all her experience to ensure she recorded a respectable distance with her first jump and then, despite a hesitant run up, put her all into a season’s best 6.43 on her second.
After consoling a dejected Johnson-Thompson, who finished her heptathlon with a slow trudge around the 800m so that she would not invalidate her entry in the long jump later this week, Ennis-Hill refocused for a javelin competition that she knew could all but secure victory.
Again, she didn’t need to approach her personal best to establish a virtually unassailable lead over Broersen, who threw a huge 53.52 to move into second, and the Canadian pre-championships favourite Brianne Theisen Eaton, who had all but blown her chances on the opening day.
Thiesen-Eaton did enough in the 8800m to claim the silver with 6554 points and the Latvian Laura Ikauniece-Admidina took bronze on 6516.
Earlier, a throw of 42.51—nine centimetres short of her season’s best—was enough to give the 29-year-old Ennis a lead of 86 points. As her opponents fell away through pressure or imperfection, she powered on.
She finished things off nervelessly in the climactic 800m, powering down the home straight to win and match her gold medal in Berlin in 2009.
Just as Mo Farah on Saturday banished the ghosts of the 2008 Olympics, when he failed to qualify for the 5,000m final on the same track, Ennis-Hill was able to forget her disappointment at missing that Games through injury.
Ennis-Hill had been undecided whether to come to Beijing and only confirmed her participation after encouraging performances in the hurdles, long jump and javelin at the Anniversary Games in London.
She had said she did not want to leave behind her one year old son Reggie and husband Andy if she did not have a realistic chance of a medal. As it turns out, this remarkable sportswoman will return with a gold around her neck.
Not only that, she has set the scene for another chapter in her stellar career in Rio next year when she will go head to head again with a Johnson-Thompson desperate to use her bitter disappointment here as fuel for the future.
Having been in contention for gold overnight, Johnson-Thompson finished 28th and last with 5,039 points, having been compelled by the rulebook to jog around her 800m in order to be allowed to compete again this week in the individual long jump.
“This time last year I’d just had my son and now I am world champion. It’s just an incredible feeling,” the 29-year-old Ennis told reporters.
“It was just a massive surprise just to be here, to be honest. I am really lost for words... If I had come here and come away with a bronze medal I would have been so, so happy. To have won the gold is even better.
“This has been the hardest year ever. Going into London (for the Olympics) was hard, with different pressures and challenges in that respect. But this year, juggling all my mummy duties and training.
“Everything has been so hard. But it’s been the most amazing year as well because I’ve got my son and now I’m here on a global stage with a world title again, which is just amazing.”
She was close to tears at the end of her 800m: “This is the last place I wanted to be right now. I had to compete.” For Ennis-Hill, the contrast could not be greater.