By SABC Sport
29th February 2024
Medvedev, playing only his second match since defeat to Jannik Sinner in the Melbourne final last month, eventually beat Sinner's compatriot 3-6 6-3 6-3.
Sonego clinched an opener in which three breaks of serve occurred before top seed Medvedev gained the upper hand with a break in the eighth game of the second set to force a decider.
A marathon fifth game of the third set lasted 14 minutes and broke Sonego's resistance, with Medvedev going on to secure another break to progress in just over two hours.
Next up for the 2023 tournament winner is Spain's Alejandro Davidovich Fokina on Thursday.
Second seed Andrey Rublev also booked his place in the last eight with a 6-4 6-4 win over Arthur Cazaux.