Nearly a year after he lost to Nadal at the Australian Open (winning just seven games in a three set loss) his game has come on immensely, he said.
The 20-year-old Australian took over as the No. 1 after the withdrawal over the weekend of Novak Djokovic.
The Australian world No. 18 was due to play his second-round singles match at Memorial Drive on Tuesday or Wednesday.
Yet on Tuesday in Adelaide, she was able to cast that result aside and overcome somewhat patchy play - as well as a stylish opponent - to secure victory.
She is keeping any thoughts of the Australian Open in check, insisting the Adelaide International was the only thing on her mind.
"It was very hard, but I like the heat and I'm happy to be here for the first time", said Bencic, who soared up the rankings previous year and won two titles, in Moscow and Dubai, on her way to a career-best 49 main-draw match wins.
The 62-minute second set was a see-sawing affair that featured six breaks of serve, including four on the trot.
"Credit to Anastasia; she hung around and got more aggressive in those latter games".
The world number one will be looking to bounce back from a shock second round exit at the hands of American Jennifer Brady at the Brisbane International last week.
The top seed is slated to run into former world No.1 and three-time grand slam champion Angelique Kerber, 2018 US Open victor Sloane Stephens, a qualifier or talented Czech Marketa Vondrousova in the quarter-finals. It's always great to get such awesome wins against the top players. "I was very surprised that so many people came today - well, not surprised because Ash was playing - but every day there were a lot of people and it was a lot of fun to play".
Elsewhere, Maria Sakkari of Greece made quick work of Vitalia Diatchenko of Russian Federation 7-5, 6-2.
The Queenslander said that facet of her game wouldn't carry any extra weight than normal at the year's first grand slam, but admitted it would always be a much-loved part of her armoury.
In the men's draw, the Briton Dan Evans, also fresh from the ATP Cup, defeated the Argentinian Juan Ignacio Londero 6-2 and 6-4, while Jeremy Chardy defeated his compatriot Gilles Simon 6-3 and 7-5. American qualifier Tommy Paul beat Aljaz Bedene 6-4, 6-4.