Sleep-deprived Russian Andrey Rublev downplays his Australian Open chances despite his hot early-season form continuing at the Adelaide International ATP tournament.

Rublev, on three hours’ sleep, advanced to the quarter-finals with a comprehensive 6-3 6-3 second-round win against American Sam Querrey on Wednesday at Memorial Drive.

The world No.18 arrived in Adelaide after winning last week in Doha – his third ATP title.

Rublev’s career-high 38 ATP wins last year included inflicting the quickest loss in 15 years on Roger Federer – a 62-minute blitz in a Cincinnati clash.

But while hoping his upward curve extends deep into the Australian Open, starting Monday in Melbourne, the 22-year-old reckons he’s still well shy of joining elite company.

“It’s (an) amazing feeling to be top 20 for the first time,” Rublev said.

“There are still so many things that I can improve; there are so many things I need to improve.

“Even if I lose first round in Australian Open, I accept this … the main goal for me is become strong mentally.

“You can (see with) Roger (Federer), Rafa (Rafael Nadal), (Novak) Djokovic, all the other top players, how mentally they are strong – me, compared to them, I’m far away.

“So in the end, doesn’t matter how good even I’m going to play at the Australian Open. If I don’t improve (the) mental part, in the end, I’m still going to be far away from them.”

Rublev, the third seed in Adelaide, will be joined in the quarter-finals by Spaniard Pablo Carreno Busta, who has defeated Frenchman Jeremy Chardy 6-3 6-2 in a second-round match.

Later on Wednesday, in another second-round encounter, Australian wildcard James Duckworth meets Canadian Felix Auger-Aliassime, the title favourite after the pre-tournament withdrawals of Djokovic and Australian Alex de Minaur.