TOKYO, Aug 4 (Reuters) - Canada"s Damian Warner rode a blistering start to take the halfway lead in the Olympic decathlon on Wednesday, tying his own world record in 100 metres and bettering the Games" best in long jump. The all-round athletics test, which covers 10 disciplines spread over two days, opened on Wednesday in sweltering conditions at the Olympic Stadium. But the heat and humidity were no problem for the 31-year-old Warner, who got proceedings underway by equalling his own world decathlon best of 10.12 seconds in the 100m. "It was kind of advertised that these were going to be the hottest Games ever. I am at my third Olympics, and I can verify that these are the hottest ones in which I have competed," Warner said. Warner arrived in Tokyo as the leading decathlete in the world in 2021 after scoring 8,995 points at a meet in Gotzis, Austria in May - the fifth best in history with France"s decathlon world record holder Kevin Mayer"s 9,126 from 2018 topping the all-time list. Warner soared to an incredible 8.24m in the long jump, four centimetres short off his world decathlon best but a new Olympic record in the sport. The leap would have earned Warner a bronze medal in the men"s long jump event ahead of Cuban Maykel Masso"s third-place finish of 8.21. Warner sent his shot put to a distance of 14.80m in the final event of the morning to open up a lead of close to 200 points over compatriot Pierce LePage. But his lead was cut in relatively better conditions in the evening by Australian Ash Moloney, who topped the high jump and the 400m to climb up to second spot. Warner totalled 4,722 points and will go into the final day with a lead of 81 over the Australian with LePage lurking in third spot on 4,529. World champion Niklas Kaul also cleared 2.11m in the high jump but the German ended up getting injured in the 400m and needed to be carried off the track in a wheelchair. Kaul was ruled out of the competition as was Belgium"s Thomas van der Plaetsen, who suffered a serious injury on his first attempt in the long jump. Warner managed 2.02 in the high jump and closed out his night with third spot in the 400m. Mayer finished the day in fifth place with 4,340 points. The participants will return on Thursday for the 110m hurdles, discus, pole vault, javelin and 1,500m.