Murray said after the match that he had considered retiring.
He lost the second set, but forced a final-set tie-breaker, before Fish won.
At the Monte-Carlo Rolex Masters, Murray suffered another first match loss, this time to Philipp Kohlschreiber.
He entered the doubles competition with Ross Hutchins; the duo lost to the Bryan Brothers on a champions tie-breaker.
This was an exhibition tournament and the only event where Murray played Rusedski, they never met on the Tour.
Rusedski beat Murray in the first match, but Murray won the second.
Coming back the next day, Murray was edged out by the eventual finalist in a tie-breaker for his second defeat by him in the year.
Following Wimbledon, Murray won Challenger events on the hard courts of Aptos and Binghamton, New York.
He then experienced his first Masters event at Cincinnati, where he beat Taylor Dent, before losing in three sets to then world No. With a wild card entry, Murray played Andrei Pavel in the opening round of the US Open, where he recovered from down two sets to one to win his first five-set match.
In the Masters tournaments Murray went out in round four in Indian Wells and the first round of Miami.
In the clay Masters Murray made the third round of Monte Carlo and Hamburg and the second of Rome.
With temperatures reaching 33 °C in the shade, Murray won the first set in a tie-breaker but began to feel ill.