Bianca Andreescu's comeback after a 15-month absence ended abruptly in the Australian Open second round on Wednesday with a 6-3 6-2 defeat to the wily Hsieh Su-wei but the Canadian leaves Melbourne Park glad her "fighting spirit" is alive.

Former U.S. Open champion Andreescu savored an emotional first-up win against lucky loser Mihaela Buzarnescu on Monday but hit a brick wall in the form of Taiwanese giantkiller Hsieh in the early match at Rod Laver Arena.

"I got off the court and I was looking at my coach, and I said I'm just disappointed that today that was my all because I know I gave my all today and to me I think that was the most disappointing part," the 20-year-old Andreescu told reporters.