Jessica Ennis will need to beat Natallia Dobrynska by around seven seconds in the 800m if she is to claim the pentathlon gold medal at the World Indoor Championships in Istanbul. A disappointing performance in the long jump has left Ennis in third place, 93 points behind the Olympic champion Dobrynska and six points behind the Lithuanian Austra Skujyte with just the 900m remaining. Jumps of 6.19m and 6.18m were followed by a foul in the final round to leave Ennis 93 points behind Ukraine\'s Dobrynska – who won the long jump with 6.57m. That left Ennis needing to beat Dobrynska by around seven seconds in the final event, the 800m – an unlikely scenario. Ennis made a superb start to her title defence at the world indoors, with a personal best in the shot put and the fastest 60 metres hurdles time in pentathlon history, and led the field after three events. \"It is Olympic year and everyone raises their game, you could see that again today,\" Ennis said at that stage. \"The long jump is the next event, and that is Tatyana\'s strong event so everything could change again.\" Ennis\'s contest with Chernova was the highlight of a satisfying morning for the British team. Yamilé Aldama, 39, qualified in first place for Saturday\'s triple jump final. Aldama leapt to 14.62m in the first round, which put her 23cm ahead of her nearest competitor. It was Aldama\'s best jump in six years, and the third longest in the world this year. Ennis made a superb start in the hurdles. She and her coach, Toni Minichiello, have been working on her technique and it showed. She sped into the lead and stayed there for a winning time of 7.91sec. Ennis has run faster only once, in Birmingham last month when she was competing in the individual event. Chernova was second, but her time of 8.29 was 0.27 down on her on personal best. That meant Ennis had a lead of 86 points over her Russia rival. That grew further still after the high jump, up to 124 points. That, though, was not as much of a gain as Ennis wanted. She cleared 1.87m, shy not just of her best of 1.95m but also the 1.90m mark she had said she wanted to break here. Those three missing centimetres cost her 39 points. Ennis had been jumping well, clearing the bar with room to spare, until she brushed it her back on her first attempt at 1.84m. That seemed to unsettle her. She failed twice at 1.87m, clearing it with her third attempt. Minichiello, passing advice from the stands, suggested that part of the finish line beam on the 60m line, placed just to left of the high jump, was infringing on Ennis\'s run-up. She had to clear her mind quickly, because 30 minutes later she was back out for the shot put. She responded superbly, with a season\'s best of 14.39m in the second round, and a personal best of 14.79m in the third. Chernova reached 13.89m with her first attempt, and then fouled twi