It is way too early to describe the situation as a crisis, but Andy Murray's recent struggles took their most serious twist yet when he lost to Mardy Fish, a journeyman American, in his opening match at the Miami Masters last night.
Murray, the defending champion, was beaten 6-4 6-4 by a 28-year-old opponent who is ranked No 101 in the world and has only ever won three minor titles. The last time that Murray lost to a player outside the world's top 100 was when he was beaten by Fabio Fognini in Canada three years ago, when the Scot was coming back from a serious wrist injury.
Serving without conviction and looking particularly vulnerable on his forehand, Murray let slip a 3-1 lead in the first set and looked increasingly out of sorts as the match progressed. At one stage the world No 3 screamed out in frustration: "What's going on?"
Fish, who has been recovering from a serious knee injury, has a big serve and powerful ground strokes but makes plenty of errors. However, his confidence quickly rose as Murray's problems grew.
Having started the season in such exhilarating fashion by reaching the Australian Open final, Murray has run into trouble at what had become one of his favourite periods of the year. The 22-year-old Scot, who has a property in Miami and trains there on a regular basis, is usually at his best playing on American hard courts, but his early exit here followed a quarter-final defeat by Robin Soderling in Indian Wells earlier this month.
This latest setback opens the way for Rafael Nadal to reclaim his world No 3 ranking and Murray is fortunate that Juan Martin del Potro, the No 5, is currently out with a wrist injury. He will now prepare for the European clay-court season and may well opt to play next in the Monte Carlo Masters next month, having originally omitted it from his schedule.
Fish beat Murray on their first meeting, but that was five years ago when the Scot was just 18. They had met three times subsequently, Murray winning in straight sets on each occasion.
A similar outcome seemed likely when Murray made the first break of serve in the fourth game with a fine backhand winner down the line. From 40-0 up in the next game, however, he let Fish off the hook, wasting game points with careless errors.
Fish broke back courtesy of two double faults and at 4-4 broke again after two horrible forehand errors by Murray. The American wasted his first set point with a lame attempt at a drop shot and should not have converted his second, but Murray put what looked to be a routine backhand into the net.
Clearly encouraged, Fish broke in the opening game of the second set, punishing a weak serve with a backhand winner down the line. When he held serve to love in the following game the American had won seven of the previous eight games.
Murray had two break points when Fish served at 4-3 only for his opponent to serve his way out of trouble. Two games later, as Fish served for the set, one ace saved a break point and another set up a match point, which he converted with a crisp volley.
Novak Djokovic, the world No 2, had gone out of the tournament 24 hours earlier, losing 6-2 6-7 6-4 to Belgium's Olivier Rochus. While the Serb tried to put a brave face on his defeat, welcoming the extra time he would have to prepare for the clay-court season, this could prove to be a significant loss, particularly after his fourth-round exit in Indian Wells. Like Murray, Djokovic usually performs well at this time of the year, having won in both Indian Wells and Miami.
Although his place behind Roger Federer in the world rankings is secure for the moment, Djokovic has dropped 665 ranking points over the last fortnight.