Murray failed to match Nadal's power and precision on clay
Andy Murray could not celebrate his 21st birthday with a landmark win as he was outclassed 6-3 6-2 by Rafael Nadal in the Hamburg Masters third round.
Nadal came into the match having struggled with fatigue and blisters, but shook off a sluggish start.
British number one Murray showed signs he is getting to grips with clay, his least favoured surface, without ever threatening to pull off a shock win.
The Scot was broken three times in the second set as Nadal dominated.
"I just want to concentrate right now on getting closer to the guys at the top," Murray told BBC Radio 5 Live.
"Whether or not I'll play as well on clay as on other surfaces, I don't really know.
"But my game is definitely getting better and that is one positive thing I can leave with."
It was a typically powerful display from Nadal, who will now face compatriot Carlos Moya in round four, and any thoughts that Murray would catch him cold after a tiring few weeks were dispelled early on.
Murray got off to the perfect start in holding to love in game one and looked capable of troubling the Spaniard on his serve early in the match.
However, it was not long before Nadal's crunching baseline game took its toll on the Scot and an overhead handed him a break at 2-1 in the first set.
Murray forged a rare opening at 3-4 when he earned two break points with some excellent approach play, but Nadal extinguished the hope swiftly, breaking again in the next game to seal the first set.
By this stage Nadal had settled into his rhythm and, even though Murray broke him to 30 at the start of the second set, the left-hander bludgeoned his way back level in the next.
There was little looking back thereafter for Nadal and when he broke Murray from 40-15 down at 1-2, the Scot's resistance was broken.
Murray was not helped by a series of unforced errors but, in truth, there was little he could do in the face of such a consummate Nadal display.
And Nadal, also 21, saw out the match in style with his third break of the set when Murray netted a forehand.
I have played a lot of tennis this year, but I am not feeling jaded or carrying any injuries
"Nadal's forehand is the best shot in tennis," said Murray. "When you go behind against him on clay it's very hard to get back."
Nadal will be joined in the fourth round by defending champion Roger Federer and world number three Novak Djokovic, while Nicolas Kiefer became the first German this century to make the quarter-finals.
Kiefer beat Nikolay Davydenko 7-5 6-3 to become the first home player to pass the third round since Tommy Haas in 1999 and he will face Italy's Andreas Seppi in Friday's quarter-final.
Federer secured his passage thanks to a 6-3 6-2 defeat of Sweden's Robin Soderling, and the Swiss insisted he is feeling fresh ahead of the French Open.
"I feel good in myself, I have played a lot of tennis this year, but I am not feeling jaded or carrying any injuries," he said. "I am looking forward to Roland Garros and then Wimbledon before I have a rest."
Having beaten Nadal in last year's final, Federer will now meet Spain's Fernando Verdasco in Friday's last eight.
Australian Open winner Djokovic, who set up a quarter-final clash with Spain's Albert Montanes with a 7-5 (7-3) 6-3 win over Croat Ivo Karlovic, is on course to meet Nadal if the pair both make it to Saturday's semi-finals.