Top-ranked Carlos Alcaraz will miss the rest of the season after suffering an abdominal muscle tear while playing at the Paris Masters.

The Spanish teenager pulled out during a second-set tiebreaker against fellow 19-year-old Holger Rune in their quarterfinal on Friday. Following medical exams, the US Open champion posted details of his injury on Saturday.

“Unfortunately this is the result of my injury: an internal oblique muscle tear in the left abdominal wall with an estimated recovery time of six weeks,” Alcaraz wrote on Twitter. “I won’t make the ATP Finals or the Davis Cup Finals. It is tough and painful for me to miss these two events, which are so important to me, but all I can do is be positive and focus on my recovery.”

The ATP Finals are scheduled for Nov. 13-20 in Turin, Italy, with the Davis Cup finals taking place Nov. 23-27 in Malaga, Spain.

The Australian Open starts on Jan. 16.

Alcaraz will be replaced at the ATP Finals by American Taylor Fritz.

Alcaraz finishes a remarkable season with a 57-13 record and five titles, including Masters trophies in Madrid and Miami. In September, he became the youngest No. 1 in the ATP computerized rankings since they began in 1973.