The Australian Open remains one of the few hard-court tournaments where Medvedev is yet to win a trophy, having lost back-to-back finals to Novak Djokovic and Rafael Nadal in 2021 and 2022.
This season, the Russian skipped the warm-up tournaments and headed straight to Melbourne, with that decision seeming to work against him as he laboured in warm conditions during his first-round match against Terence Atmane.
A sapped Medvedev ultimately progressed when his French opponent retired due to injury.
"I feel, for whatever reason, I don't know, a little worse in these conditions than some other tournaments," the world number three told reporters ahead of the second-round clash with Finland's Ruusuvuori.
"At the same time I was two times in the final, and one I was really close to winning. So I really hope I can show my best tennis one time here, at least one, and win it.
"It's the first tournament of the year. Even if you have a warm-up tournament, it's still kind of the beginning of the year, so the sensations are different."
Elsewhere, Carlos Alcaraz will face Lorenzo Sonego on Rod Laver Arena, and though the Italian has a 1-0 winning record against the second-seeded Spaniard, a lot has changed since the two last faced off in 2021.
"He was really young. He's different now," Sonego told ATPTour.com. "He was (outside the top) 50 in the world. Now he is No. 2. Yeah, he improved a lot in tennis, and I need to do my best to beat him."
Before Alcaraz and Sonego meet, action begins on the main showcourt with world number one Iga Swiatek taking on former finalist Danielle Collins.
While the four-time Grand Slam champion has a 4-1 head-to-head record against the American, her only defeat by Collins came in a semi-final at Melbourne Park two years ago.
Another tasty clash in the women's singles sees local hope Ajla Tomljanovic take on 2017 French Open champion Jelena Ostapenko.
The pair had an ugly exchange at Wimbledon in 2021 when the Australian accused her of faking an injury to have a medical time-out, but Tomljanovic has insisted there is no longer any bad blood, saying, "what happened, happened".
