Despite a current ATP world ranking of 752nd, Ruusuvuori was able to enter the tournament via the protected ranking system, having been suffering with recent injuries and mental health issues. The 26-year-old has spoken openly about the panic attacks he has suffered in recent months.
Popyrin showed no mercy, breaking the Finn in his first service game and racing into a 3-0 lead. Ruusuvuori saved three break points in the fourth game to finally get something on the board, but the remainder of the first set went with serve, giving the Australian a 6-3 victory.
The second set saw the world number 36 break Ruusuvuori twice without dropping a single point, yet remarkably on both occasions the Helskinki man broke back in the following game.
However, when Popyrin broke for a third time to go 5-4 ahead, he held the next game with ease to go two sets in front.
One break of serve each in the third set sent it to a tiebreak, and two losses of serve for Ruusuvuori helped Popyrin on the way to four match points. The Finn saved the first, but couldn't prevent the Sydney man wrapping up the win in straight sets.
The 6-3, 6-4, 7-6 win for the Australian sets up the small matter of a Second Round match with defending champion and number one seed Jannik Sinner.