Novak Djokovic
Novak Djokovic lost to Martin Klizan in three sets Wednesday, April 25.Alex Caparros/Getty Images

World number one Rafael Nadal insisted he is expecting tough tests in the final rounds of the ongoing ATP 500 tournament in Barcelona despite the exits of Novak Djokovic and Kei Nishikori in the R16 rounds.

Djokovic, who had recovered from issues with his injury-prone wrist to reach the R16 round in Monte Carlo Masters last week, suffered a shock second-round exit in Barcelona on Wednesday, April 26.

The 12-time Grand Slam champion, seeded sixth at the ongoing tournament, was stunned by qualifier Martin Klizan 6-2, 1-6, 6-3 in a 98-minute Round of 32 encounter. After racing to a comfortable first-set win, the Serb was decimated despite winning 71% of points on his first serve.

On the other hand, 14th seed Kei Nishikori retired from his second-round match against world number 69 Guillermo Garcia-Lopez after conceding the first set 6-3 due to recurrence of a wrist injury that has been hampering his performances for quite some time now.

Notably, Nadal was expected to face Nishikori, whom he defeated in the final of Monte Carlo on Sunday, in Thursday's Round of 16 match. A potential semi-final clash against Djokovic was also on the cards for the Spaniard.

"The reality is that they have lost two of the best players in the world, but that does not mean that tomorrow he does not have a very difficult match against Guillermo Garcia-Lopez. My motivation and my hope is to do my best and compete well every week, the rivals also want to win, not just play," Nadal said, as quoted by Daily Express.

"He [Garcia-Lopez] is aggressive, he has good punches and good service, he will not go out on the court without believing he can win, he has experience in important matches. I have to be prepared to play better than today," the 10-time champion added.

Nadal on a record-breaking spree

Rafael Nadal
Rafael Nadal is on course for a 11th title in Barcelona.JOSEP LAGO/AFP/Getty Images

Meanwhile, Nadal had extended his tally of winning successive sets on clay-court to world record 38 Wednesday when he outclassed compatriot Roberto Carballes Baena 6-4, 6-4.

The 31-year-old, who won his 11th Monte Carlo Masters title last week, had to save a break point in the first set and traded breaks with his 25-year-old opponent in the second set before serving out the match.

Nadal, who now has 54 wins from 57 matches in Barcelona, will face Garcia-Lopez, whom he has beaten four times in their five career meetings, on Thursday.