<Tr> <Td> ← 2016 </Td> <Td> Australian Open </Td> <Td> 2018 → </Td> </Tr> <P> Novak Djokovic was the two - time defending champion, but lost in the second round to the 117th ranked Denis Istomin from Uzbekistan . It was the first time since the 2008 Wimbledon Championships, where he lost to Marat Safin, that Djokovic failed to make it past the second round of a major and the first time since the 2006 Australian Open that he failed to make it to the third round in Melbourne . </P> <P> Roger Federer won his fifth Australian Open title, and 18th Major title overall, defeating Rafael Nadal in the final in five sets . With the win, Federer became the first male player to win at least five titles at three Grand Slam tournaments (five at the Australian Open, seven at Wimbledon and five at the US Open). </P> <P> This was the first Grand Slam tournament in which Andy Murray started as World No. 1 and top seed . Murray retained the top ranking despite losing to Mischa Zverev in the fourth round, because second seeded Djokovic needed to win the tournament to regain the No. 1 ranking, but lost in the second round . This was the first time since the 2004 French Open that the top two men's seeds both failed to make it past the fourth round of a major . </P>

Who win the 2017 australian men's open tennis single title
find me the text answering this question