<p> Tunisia's Ahmed Hafnaoui pulled off a major shock on the opening day of the Tokyo Olympics swimming medal events with a stunning victory in the men's 400m freestyle, while American Chase Kalisz powered to victory in the men's 400m medley on Sunday.</p>.<p>The 18-year-old Tunisian, in the outside lane after being the slowest in qualifying, produced a blistering finish to pip Australia's Jack McLoughlin to gold with a time of 3:43.36, with U.S. swimmer Kieran Smith taking bronze.</p>.<p>Kalisz, the 400 medley silver medallist in Rio, went one better with a time of 4:09.42 as part of a United States one-two with Jay Litherland 0.86 behind.</p>.<p><strong><a href="https://www.deccanherald.com/sports/tokyo-olympics-live-Tokyo2020-Olympics-TokyoOlympics-Japan-Covid19-coronavirus-Tokyo-Tokyogames-Japanolympics-1012570.html" target="_blank">Live updates from Tokyo Olympics on DH</a></strong></p>.<p>Australia's Brendon Smith was a further tenth of a second back taking bronze.</p>.<p>Kalisz, 27, grabbed the lead on the first length of the backstroke after France's Leon Marchand had led after the butterfly leg and never looked back.</p>.<p>He battled with New Zealand's Lewis Clareburt through the breaststroke but the Kiwi faded badly in the freestyle and finished seventh.</p>.<p>"It means the world. This is the last thing that I really wanted to accomplish in my swimming career," said Kalisz.</p>.<p>"It was something that was a dream of mine for as long as I could remember. I can't believe it."</p>
<p> Tunisia's Ahmed Hafnaoui pulled off a major shock on the opening day of the Tokyo Olympics swimming medal events with a stunning victory in the men's 400m freestyle, while American Chase Kalisz powered to victory in the men's 400m medley on Sunday.</p>.<p>The 18-year-old Tunisian, in the outside lane after being the slowest in qualifying, produced a blistering finish to pip Australia's Jack McLoughlin to gold with a time of 3:43.36, with U.S. swimmer Kieran Smith taking bronze.</p>.<p>Kalisz, the 400 medley silver medallist in Rio, went one better with a time of 4:09.42 as part of a United States one-two with Jay Litherland 0.86 behind.</p>.<p><strong><a href="https://www.deccanherald.com/sports/tokyo-olympics-live-Tokyo2020-Olympics-TokyoOlympics-Japan-Covid19-coronavirus-Tokyo-Tokyogames-Japanolympics-1012570.html" target="_blank">Live updates from Tokyo Olympics on DH</a></strong></p>.<p>Australia's Brendon Smith was a further tenth of a second back taking bronze.</p>.<p>Kalisz, 27, grabbed the lead on the first length of the backstroke after France's Leon Marchand had led after the butterfly leg and never looked back.</p>.<p>He battled with New Zealand's Lewis Clareburt through the breaststroke but the Kiwi faded badly in the freestyle and finished seventh.</p>.<p>"It means the world. This is the last thing that I really wanted to accomplish in my swimming career," said Kalisz.</p>.<p>"It was something that was a dream of mine for as long as I could remember. I can't believe it."</p>