Rafael Nadal produced a false start in the long quest to rediscover his Wimbledon touch by falling at the first hurdle to Alex Dolgopolov at the Aegon Championships.
he 2008 champion slipped out 6-3 6-7 (6/8) 6-4 in his first return to Queen's Club in four years, owing to relaxed UK tax rules for overseas sports stars.
Nadal has talked of attacking Wimbledon now he is finally past all manner of knee problems, and arrived in west London after claiming the Mercedes Cup title at Stuttgart - his first on grass in five years.
The 29-year-old has already admitted this week "I was not surprised that I lost" to Novak Djokovic in the French Open quarter-finals, relinquishing the Roland Garros title for the first time since 2009.
That faltering form came back to haunt the 14-time grand slam champion, as despite leading the final set 4-2 Nadal was reined in and beaten for the second time in succession by his Ukrainian opponent.
Nadal saved a match point in the second-set tie break and then looked ready to rally for victory, but was unable to hold his nerve.
Chelsea boss Jose Mourinho watched on as Nadal, a big fan of the Portuguese's former club Real Madrid, was unable to sustain his fine start to the grass court campaign.
Nadal has not reached a Wimbledon quarter-final since 2011 when he finished runner-up at SW19, and will still aim to set his London record straight at the end of the month.
Dolgopolov will now face Guillermo Garcia-Lopez in second-round action at Queen's.
Mourinho gave his verdict on the match afterwards, the Chelsea boss telling BBC Sport: "I'm Rafa's friend so I have to say I'm not happy with the match. But I'm happy with the Rafa I saw."