Olympics-Athletics-Toth overhauls Tallent to win 50km walk gold

* Toth adds Olympic title to world crown * Tallent crosses line second for third straight Games * Dunfee gets bronze after Arai disqualified (Adds Arai disqualification, details and quotes) By Nick Mulvenney RIO DE JANEIRO, Aug 19 (Reuters) - Matej Toth of Slovakia overhauled reigning champion Jared Tallent with a perfectly timed surge on the last circuit of the Rio road track on Friday to add the 50km walk Olympic title to the world crown he won last year. The 33-year-old journalist blew kisses to the crowd as he walked the final kilometre of the gruelling test of endurance before completing the course in three hours 40.58 minutes to win his first medal at his fourth Games. "It's something unbelievable for me," Toth told reporters. "Something like immortality in sport. I'm so proud. So happy. It's a great feeling." Australia's Tallent, who led the race for much of the final 10 kilometres, crossed the line in second place for the third Games in a row, 18 seconds behind Toth. Japan's Hirooki Arai finished a further six seconds back but was later disqualified, leaving Canada's Evan Dunfee to take the bronze medal in 3:41.38. The Japanese prompted a protest from the Canadian team after barging Dunfee in the back as he passed him for the final time, leaving the Canadian shaking his hands in frustration. Another silver medal was a huge disappointment for Tallent as both his previous second-place finishes had come behind athletes who were subsequently banned for doping. He was awarded a London gold medal in a special ceremony earlier this year after Russian Sergey Kirdyapkin was stripped of the title, but Alex Schwazer, the 2008 Olympic champion, retains his gold medal despite his conviction. "I wanted to win," said the 31-year-old Tallent. "That was the main aim after what happened in London. Getting the gold medal so late, and to be an Olympic champion for more than a few months. "I gave it everything but probably went a little bit too early. Then Matej caught me with about a lap to go and I just had nothing in the legs. Just couldn't hold on." World-record holder Yohann Diniz gave the world a graphic illustration of the demands of the race, particularly when played out in energy-sapping heat and bright sunshine. The Frenchman tore off at a terrific pace and held a lead of one minute 40 seconds at the halfway mark before coming to a grinding halt some 38 kms into the race. He resumed alongside Canada's Dunfee after the field caught up with him but, clearly suffering from a stomach upset, lurched around the track and collapsed on the tarmac before incredibly completing the race in fifth place. "Today was very tough," said Toth, who also pushed Tallent into second place at last year's Beijing world championships. "Compared with Beijing last year, which was one of the easiest 50km races, this was one of the hardest. It was very tough. It was very warm." Russia has traditionally been a powerhouse in the sport but was unrepresented in the race after a string of doping convictions that preceded the almost blanket ban on the country's athletes at the Games. (Editing by Alison Williams and Clare Fallon)