Ben Shelton lost to Jannik Sinner in the semi-finals of last year's Australian Open, with the pair squaring off in the last eight in 2026.
World number two Iga Swiatek and fifth seed Elena Rybakina both breezed into the Australian Open quarter-finals.
Jannik Sinner eased into the Australian Open quarter-finals by defeating fellow Italian Luciano Darderi in straight sets on Monday.
Madison Keys claimed a shock win at the Australian Open last year, but the reigning champion saw her title defence ended by Jessica Pegula.
Rublev survives a three-and-a-half-hour epic to beat Popyrin and reach the last-16 in Cincinnati
A break in each set was enough to see Carlos Alcaraz beat Hamad Medjedovic & secure his 50th win of the season
Two unusual interruptions don't distract Jannik Sinner in his win over Gabriel Diallo
Holger Rune eased past American Alex Michelsen to reach the round of 16 at the Cincinnati Open