Struggling after winning your first major is nothing unusual as many players expect it. Medvedev won one and he's yet to win another one. Thiem openly spoke about losing motivation following his win at the US Open and Alcaraz had some struggles as well.
I had a bad period after I won the US Open. That sounds like I’m making it up, but…well, I enjoyed that moment a lot. But the truth is, when I had to go back into competition, there was a point when I went: ‘Stress!’ You know?."I think what happened was, when I saw that I’d achieved what I’d dreamed of since I was a little kid, unconsciously that aspiration dimmed a bit.
The Spaniard experienced some disappointing results following the US Open and injuries certainly didn't help him. It was tough to deal with because neither he or his coach enjoyed that time at all.
And that was hard. Because no one was enjoying it—I wasn’t, on the court; Juanki (Note – his coach Juan Carlos Ferrero) wasn’t, seeing me so shut down and lacking in spark. I thought, Where do I go now?”