Bernard Tomic’s commitment to tennis is expected to come under the microscope again after the Australian pulled out of his first round match in Acapulco citing “unbearable heat”.

Tomic lost the first set to American Donald Young in a tiebreak but looked disinterested and lethargic at stages before withdrawing from the match.

The loss ruled out a potential second round clash with compatriot Nick Kyrgios who is playing later on Tuesday.