Rafael Nadal suffered a shock first round exit from the Wimbledon warm-up event at Queen's Club as the Spanish star was beaten 6-3, 6-7 (6/8), 6-4 by unheralded Ukrainian Alexandr Dolgopolov on Tuesday.
Nadal's dismal defeat against the world number 79 is the latest in a growing list of lacklustre performances in a troubled 2015 campaign for the former world number one.
The 14-time Grand Slam winner was beaten at the French Open for only the second time in his glittering career when Novak Djokovic won their quarter-final clash in Paris.
As a result, Nadal's ranking has plunged to 10th -- his lowest position for a decade -- and to add insult to injury he will now head to Wimbledon, which gets underway later this month, with renewed questions about a decline that hit another low with this setback in west London.
It was the second time this year Nadal had lost to an opponent outside the top 50 after his January defeat to world number 127 Michael Berrer.
Nadal, back at Queen's for the first time in four years, wasn't expected to have any problems with Dolgopolov after the confidence booster of winning the grass-court tournament in Stuttgart last week -- his first title on the surface since lifting the Wimbledon crown five years ago.
He even had Jose Mourinho in his corner as the Chelsea manager sat courtside just behind Nadal's uncle and coach Toni.
Yet it was Dolgopolov who forced the pace and the 26-year-old from Kiev secured the first break in the second game, unfurling a spectacular cross-court forehand winner on the run.
Dolgopolov came into the tournament on a three-match losing streak, but he had won his last meeting with Nadal -- at Indian Wells last year -- and continued to dominate from the baseline as he closed out the set.
In a dramatic second set tie-break, a blistering forehand at 5-5 gave Dolgopolov a match point, but Nadal saved it with a nerveless serve.
The fifth seed then produced a perfectly-timed volley to secure a set point that he converted when Dolgopolov dragged a backhand wide.
Nadal looked firmly in control after breaking in the third game of the final set, but he let the momentum, and a 4-2 lead, slip away when, after being given a warning for a time violation, he allowed Dolgopolov to break back.
There was more frustration for Nadal at 4-4 when he wasted three break points and that proved the decisive moment when Dolgopolov unloaded a searing winner on match-point in the next game to steal a sensational victory.
Earlier, French Open champion Stanislas Wawrinka gave short shrift to Nick Kyrgios's claims that his 6-3, 6-4 victory was the result of the Australian's physical and mental fatigue.
The Swiss second seed swept through his first round clash in just 49 minutes to set up a second round meeting with big-serving South African Kevin Anderson.
But, while Wawrinka was on top form, emerging star Kyrgios attributed his poor performance to an illness and home sickness after a lengthy spell on the road.
"I've been sick for the last week. I'm obviously not feeling great," Kyrgios said.
"I almost found it difficult to get myself engaged and didn't want to be there. I've been battling mentally a bit."
Wawrinka, however, was unimpressed by Kyrgios's complaints and said the brash youngster's comments in press conferences had to be taken with a pinch of salt.
"I think he's saying a lot of things every day. It doesn't really surprise me," he said.
"I read before the match he was ready, excited for the challenge, and now he was sick."
Meanwhile, defending Queen's champion Grigor Dimitrov moved into the second round with a 4-6, 6-3, 6-4 victory against 2010 winner Sam Querrey.
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