Olympics-Athletics-Briton Ennis-Hill on course for heptathlon repeat

By Mitch Phillips RIO DE JANEIRO, Aug 12 (Reuters) - Briton Jessica Ennis-Hill made an excellent start to the defence of her Olympic heptathlon title on Friday to lead after four events overnight, but her compatriot Katarina Johnson-Thompson is up against it after a shot-put disaster. Ennis-Hill, who came back from having a baby to win the world championship last year, was solid all day while her younger rivals oscillated. She opened up with an impressive 12.84 seconds 100 metres hurdles on a wet track, then cleared a season's best of 1.89m - her second-best jump at a global championships - in the high jump. A solid shot kept her well placed and a 200m of 23.49, second-best on the night, left her in the lead on 4,057 points. Johnson-Thompson, touted by many to be Ennis-Hill's biggest threat, cleared a British high jump record of 1.98 metres to lead after two events, but had an appalling shot best of 11.68 to plummet to sixth. Johnson-Thompson was in contention in the world championships last year before three fouls in the long jump stopped her in her tracks and she looked similarly distraught after her shot effort. "She would have been better off doing a standing throw," said exasperated 2000 Olympic champion Denise Lewis in commentary for the BBC. Johnson-Thompson came back with the day's fastest 200m to end the day fourth, 100 points off the pace. Between the two Britons are two 21-year-olds - Belgium's Nafissatou Thiam and Akela Jones of Barbados. Thiam also cleared a personal best 1.98m in the high jump and launched the shot a competition-best 14.91 metres to take the lead, before a sluggish 25.10 in the 200 slipped her back to second on 3,985. Jones, after an excellent hurdles and high jump, is third on 3,964 points. (Editing by Ed Osmond)