Brisbane, Australia (SportsNetwork.com) - Fifth-seeded Kevin Anderson and defending champion Lleyton Hewitt opened their seasons with a loss, while Alexandr Dolgopolov was a first-round winner Tuesday at the Brisbane International tennis event.

Polish qualifier Lukasz Kubot upset the 6-foot-8 Anderson 7-6 (7-3), 6-4, while the 2012 runner-up and seventh-seeded Ukrainian Dolgopolov dismissed Argentine Carlos Berlocq 6-2, 6-3 on the hardcourts at Queensland Tennis Centre.

Meanwhile, an all-Aussie affair saw big-serving Sam Groth pop 14 aces in taking out the former world No. 1 star Hewitt 6-3, 6-2. The three-time Brisbane champ and former runner-up Hewitt stunned this week's top seed, Roger Federer, in last year's all-former world No. 1s finale.

In matches involving Americans on Day 3, Steve Johnson outlasted Aussie Marinko Matosevic 2-6, 7-6 (7-0), 7-5, Aussie wild card John Millman mauled qualifier Rhyne Williams 6-3, 6-1, and Finnish veteran and 2008 runner-up Jarkko Nieminen overcame qualifier Denis Kudla 4-6, 6-1, 6-4. Millman will meet a top-seeded Federer here on Thursday.

Additional wins came for Slovak Martin Klizan and Kazakhstan's Mikhail Kukushkin.

In some second-round action on Wednesday, second-seeded U.S. Open runner-up Kei Nishikori will take on the two-time NCAA singles champion Johnson and fourth-seeded 2013 Brisbane runner-up Grigor Dimitrov will encounter Frenchman Jeremy Chardy.

Brisbane serves as a tune-up for the Australian Open, which will begin January 19 in Melbourne.