Nick Kyrgios has been fined almost $A40,000 by the ATP on Wednesday after walking off the court during his opening match at the Shanghai Masters a day earlier.

The 13th-seed packed his bag and left the court after losing the first set 7-6 (75) to Steve Johnson on Tuesday.

Kyrgios was fined his first-round prize money of $A27,071, for failing to see the doctor following his retirement. According to ATP Tour rules, it is mandatory to be examined by a physician if injured. He was fined an additional $A12,840 for unsportsmanlike conduct.

Hours after he abandoned the match, Kyrgios offered an apology on Twitter and said he had a stomach ache and sore shoulder.

This was despite television footage and audio capturing him telling his courtside box he’d quit after the first set in an apparent protest over the decisions of chair umpire Fergus Murphy.

Kyrgios received a warning during the 12th game of the first set after hitting two balls in anger. During the tiebreaker, he was docked a point for inappropriate language.

The dramatic walk-off came after the volatile star was suspended from the ATP Tour for tanking at the very same tournament in China 12 months ago.

Kyrgios has subsequently also withdrawn from the doubles tournament in Shanghai.