World number one Rafael Nadal will launch his campaign to equal Roger Federer's record of 20 Grand Slam titles when he plays Hugo Dellien at the rain-hit Australian Open on Tuesday. Only one of the snarling Spaniard's 19 Major wins have come in Melbourne, meaning Nadal can also become the first man in the Open era to win all four Grand Slam tournaments at least twice. An upset looks unlikely against Bolivia's Dellien, the world number 73 who is making his Australian Open debut and facing a top-ranked player for the first time. After the opening day was disrupted by heavy rain, with 17 matches postponed, play will begin 30 minutes early on the outer courts in an attempt to clear the backlog. Women's number two Karolina Pliskova is first up on centre court against France's Kristina Mladenovic, before unseeded five-time Grand Slam winner Maria Sharapova plays Croatia's Donna Vekic. Perhaps the clash of the day features Russia's Daniil Medvedev, who took Nadal to five sets in last year's US Open final, against 2019 Melbourne quarter-finalist Frances Tiafoe of America. Tiafoe, Medvedev's contemporary at 23, beat seeds Kevin Anderson and Grigor Dimitrov before falling to Nadal last year. He will need similar form on Tuesday against the widely tipped world number four Medvedev. Australia's Nick Kyrgios, who has spearheaded fundraising efforts for the country's deadly bushfire disaster, opens his campaign against Lorenzo Sonego of Italy. Switzerland's Stan Wawrinka, the 2014 champion, plays Bosnian Damir Dzumhur, and German seventh seed Alexander Zverev will bid to put some early season defeats behind him when he faces Italy's Marco Cecchinato. Former world number one Angelique Kerber, the 2016 champion, rounds off the evening on Rod Laver Arena against unseeded Italian Elisabetta Cocciaretto. th/pst