Bernard Tomic is vowing to fight to save his career as he faces the humiliating prospect of having to qualify for the Australian Open following a disastrous first-round US Open loss in New York.

In his first match since being fined a Wimbledon-record $US15,000 for saying he was "a little bored" during his first-round defeat at the All England Club, Tomic succumbed 3-6 6-3 6-4 6-4 to 19th seed Gilles Muller.

Tomic is provisionally projected to slump to 142nd in the rankings, leaving the one-time grand slam quarter-finalist and world No.17 very much at a career crossroads.

Unless he improves his ranking to around 105 by the end of the season, the 24-year-old will miss direct entry to his home major.