From the baseline, the Swede in the fourth set tiebreak could see the Spanish star shot Carlos Alcaraz hit the ball a few decimetres too far and thus state that the match was over.
After 2-6, 6-4, 6-4, 7-6 (7-5), he is now ready for the third round.
The match offered many and long baseline duels, often conducted by Alcaraz.
When one of the players went towards the net, it was usually Ymer who got the point.
In the next round, Ymer will take on fifth-seeded Greek Stefanos Tsitsipas or home jumper Thanasi Kokkinakis, who got a place in this year's first grand slam tournament via a wild card.
CLIP: See Mikael Ymer's match ball that took him further (January 9)
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Ymer won the match after 3 hours and 44 minutes.
Photo: TT