Sinner emerged earlier than Alcaraz on the ATP Tour, as fans have known him for a few years. Yet, the rise of the Spanish player was quicker and more dramatic, which is why he overtook Sinner as the most promising young tennis player in many people's eyes.
However, things have changed recently, especially as Sinner finally took the next step by winning his maiden Grand Slam final. The rivalry was booming anyway, as they had played a couple of important matches already with varying results.
It's only going to get better in the future, as they've started to practice together from time to time, and many players predict them to be the next big rivalry. Toni Nadal agrees as he wrote for El Pais about Sinner and his Australian Open triumph.
"When a player's shots are no longer enough to win, he has no choice but to resort to tactics. But Medvedev didn't even have a choice. The Italian's power and precision completely destroyed him."
The match was an important indicator for Nadal, who is convinced that it is the start of a changing tennis landscape. Sinner arrived on the big stage, and his arrival changed things quite a bit, essentially cementing himself as Alcaraz's main rival but also a consistent threat for the Grand Slam trophies.
"Once the Sinner and Medvedev match was over, I commented on the match with my children. I fear that this big and significant step could change the landscape of tennis in the coming years. Although Sinner had long been considered Alcaraz's most likely rival, he lacked a victory of that magnitude to back it up. He will be our tennis player's biggest rival in the coming years."