The 18-year-old Gauff is now unbeaten in seven matches this year having won the ASB Classic in Auckland earlier this month.
Against Raducanu, the 2021 US Open champion, she faced arguably her sternest test of the year so far, and the much-anticipated encounter certainly lived up to its billing.
Both players produced high-quality shots at crucial moments, but it was Gauff, seeded seventh for the tournament, who had the upper hand throughout.
“Considering the circumstances, I can imagine both of us were nervous,” Gauff said in her on-court interview. “This was a long-anticipated match-up basically since the draw came out, so I’m glad that it was a good match for you guys.”
The pair exchanged breaks at the start of the match, but Gauff seized the advantage when she broke for a 4-2 lead and served out for the first set.
It looked like the American would cruise through the rest of the match when she took a 3-1 lead in the second set, but Raducanu clawed her way back into the contest and broke Gauff to love at 3-4.
Time and again, the two players found themselves locked in long, absorbing rallies, and Raducanu came close to leveling the match with two set points at 5-4.
Gauff, however, was moving superbly around the court, retrieving shots that seemed well out of her reach. Her serve also proved a reliable weapon when she needed it most as she took the second set to a tiebreak.
Raducanu, unable to sustain her high level from earlier in the set, slipped to a 2-6 deficit in the tiebreak, and from there Gauff saw out the contest by sending a lob over Raducanu on the third of her four match points.
Having started the Australian Open as one of the pre-tournament favorites, Gauff will step up her pursuit of a first grand slam title against either China’s Zheng Qinwen or American compatriot Bernarda Pera in the third round.
For the 20-year-old Raducanu, the defeat ended a difficult start to the year having rolled her ankle during her second-round match in Auckland.
She has struggled with form and injury since winning her first grand slam as an 18-year-old qualifier and dropped to 77th in the world rankings ahead of the Australian Open.