The Austrian has not been the same player since he went down with a wrist injury in the summer of 2021.
The American made a big decision earlier this year and she believes it will help her get to the next level.
"Every loss kind of weighs on me heavy, especially one where I felt like I could have done better," Coco Gauff said.
The 24-year-old has won 13 of his first 16 matches at Masters events.
The pair traded smiles -- and miraculously good shots -- on Monday in Miami.
"Goes without saying this is a tough one to take and I’ll be out for an extended period," former world No. 1 Andy Murray said.
Two Kazakhstan women are among the last eight still standing in Miami.
