PARIS (Reuters) - Novak Djokovic felt "more nervous than usual" as he faced his first serious test at the French Open on Saturday but continued his amazing unbeaten run by knocking out Juan Martin Del Potro to reach the fourth round.
World number two Djokovic, who has a 40-0 record this year including his triumph at the Australian Open, triumphed 6-3 3-6 6-3 6-2 against the 2009 U.S. Open champion in a match played over two days.
"I went into the match a bit more nervous than usual," Djokovic, who is bidding to break John McEnroe's record of 42 straight wins since the start of a year, told a news conference.
He was only facing such a quality player at this stage because Del Potro has tumbled down the rankings after injury problems.
"We both made a lot of unforced errors at the start and then had some great, great periods of the match when we both played well," added Djokovic.
"I was aware if I lost the serve it was going to be very difficult to get it back."
When they resumed on Saturday, Del Potro set up two break points in the fifth game of the third set but could not convert and in the following game, Djokovic broke to love as he put the Argentine on the ropes.
Djokovic, who is also on a 42-match winning streak since last December, ended the contest with an exquisite drop shot to set up a meeting with local favorite and 13th seed Richard Gasquet for a place in the quarter-finals.
Del Potro only had a mini-moan about losing his impetus from Friday.
"It's my second time suspending matches to the next day. It's not usual but can happen sometimes, and it's the same conditions for both players," the 25th seed said.
"Today he's done much better than me and he took his opportunities and made the match very difficult."
(Reporting by Julien Pretot and Mark Meadows; Editing by John Mehaffey and Pritha Sarkar)
