MELBOURNE - Lest anyone get the idea that Stefanos Tsitsipas' upset of Roger Federer was a fluke, the 20-year-old Greek followed it up by beating No 22 seed Roberto Bautista Agut 7-5, 4-6, 6-4, 7-6 (2) at the Australian Open on Tuesday to become the youngest Grand Slam semifinalist since 2007.

"That was a great win. It got people's attention," Tsitsipas said about his fourth-round stunner against two-time defending champion Federer on Sunday.

"My biggest challenge was to stay concentrated, stay focused in order to show it didn't happen accidentally."

Cheered on by a loud, flag-waving contingent of Greek fans inside and outside Rod Laver Arena, Tsitsipas again displayed his varied skill set against Bautista Augut, with 22 aces, 30 more winners than unforced errors (68-38) and a nose for getting to the net.