Australia's Alex de Minaur celebrates a point against Stefanos Tsitsipas, of Greece, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Stefanos Tsitsipas of Greece, hits a forehand to Australia's Alex de Minaur, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Australia's Alex de Minaur follows through on a return to Stefanos Tsitsipas, of Greece, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Stefanos Tsitsipas, of Greece, reaches for a shot from Australia's Alex de Minaur during a Mexican Open tennis tournament match in Acapulco, Mexico.

Holger Rune, of Denmark, celebrates after defeating Dominik Koepfer, of Germany, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Holger Rune, of Denmark, celebrates after defeating Dominik Koepfer, of Germany, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Dominik Koepfer, of Germany, hits a backhand to Holger Rune, of Denmark, during a Mexican Open tennis tournament match in Acapulco, Mexico.

Dominik Koepfer, of Germany, hits a return to Holger Rune, of Denmark, during a Mexican Open tennis tournament match in Acapulco, Mexico.