London:Rafael Nadal still looked hampered by his injured knees in an unsuccessful transition to grass on Thursday and will decide on Friday whether he is fit enough to defend his Wimbledon title.
Nadal played without tape on his sore knees but frequently looked a step slow in losing 6-4, 6-3 to Lleyton Hewitt in an exhibition match at the Hurlingham Club in London.
It was Nadal's first match after losing to Robin Soderling in the fourth round of the French Open. He pulled out of last week's grass-court tournament at Queen's Club to rest his knees.
However, Nadal looked increasingly frustrated against the hard-serving Hewitt as he repeatedly failed to get to balls he would normally reach and struggled with unforced backhand errors.
Nadal did not speak to reporters, but his uncle and coach Toni said it was still uncertain whether he can play at Wimbledon, which starts Monday.
Nadal plays another two-set exhibition match against Stanislas Wawrinka on Friday, and Toni Nadal said the top-ranked player will make a decision after that.
"It's the first match (on grass), and we'll have to wait until tomorrow," Toni Nadal said. "I don't know. We'll have to wait until tomorrow, and we'll see then."
When pressed about Nadal's chances of playing at Wimbledon, his coach did not sound optimistic.
"If it's me, I'm (flying) to Mallorca," he said, referring to the island Nadal grew up on.
Hewitt challenged Nadal from the start at the small private club by the bank of the River Thames, forcing the Spaniard to save two break points in the first game before holding serve.
The former top-ranked Australian then managed to break to love for a 3-2 lead after three unforced errors from Nadal, and held his next service game to love behind a barrage of aces.
Nadal frequently muttered to himself in Spanish after missing shots, and often had to rely on his topspin forehand to bail him out of trouble.
Nadal had his first break point in the first game of the second set, but Hewitt saved it with a service winner. Nadal set up another break point at 2-2 with a good forehand volley, but Hewitt made a forehand winner down the line before holding.
Hewitt then broke again for a decisive 4-3 lead after Nadal sent a forehand long, and the Australian converted his second match point after Nadal sent a lunging backhand long as well.
In the other singles match on Thursday, Tomas Berdych beat Marat Safin 7-6 (7), 6-4.