Britain's Andy Murray and Tim Henman both failed to reach the quarter-finals of the Madrid Masters.
Henman and Murray both lacked consistency
Murray lost to 1-6 7-5 6-3 to Serbia's Novak Djokovic, while Henman's run was halted by a 6-2 2-6 7-5 defeat by David Nalbandian of Argentina.
Murray looked likely to beat his fellow 19-year-old after racing away with the opening set of their third-round match.
But Djokovic recovered well to take the second, and an increasingly unhappy Murray went off the boil in the third.
Early on, Murray looked composed and business-like, breaking his opponent in two successive games as he romped to the first set.
The second was a more cagey affair, but when he managed the first break of the second set for 4-3, it looked like Murray was on his way to the last eight.
I was very disappointed to lose that match as I was pretty much on top of him
But he was promptly broken straight back, and when the Serb broke him again for the second time in three games, it gave him the set 7-5 and the momentum of the game changed in Djokovic's favour.
Murray clearly began to unravel as he went 0-3 down in the third set, and although he did at least restore some pride, the outcome was not hard to see.
The match ended in bizarre circumstances, however, as the players came to the net to shake hands after a long return by Murray, only for the umpire to overrule the line judge.
But it was only a temporary respite, as all too appropriately another Murray error wrapped up Djokovic's comeback win.
"Obviously I was very disappointed to lose that match as I was pretty much on top of him, but I served really badly today," said Murray.
"But it's been a pretty good tournament for me even though I would have liked to have gone on for longer."
Earlier in Madrid, British number two Henman had a chance to serve for the match when he led 5-4 in the decider, but Nalbandian got a crucial break.
He also had two break points in the next game but Nalbandian recovered and broke to clinch a hard-fought victory on his second match point.
It was Nalbandian's fifth win in six meetings with the Briton and the former Wimbledon runner-up made the best possible start sweeping through the first set.
But Henman broke immediately in the next to give the match a different look and it soon became a double break as he set up a deciding set
They shared the opening four games before Henman made his move, breaking and then maintaining the break.
Nalbandian had to serve to stay in the match at 5-3 down but held his nerve and took advantage with Henman struggling.
The pair exchanged angry words at 5-5 in the decider and Henman claimed afterwards that the Argentine had questioned his sportsmanship.
"If you're going to go down that road, there's only going to be one winner in that debate," he said.