(CNN) -- World No.2 Novak Djokovic extended his season's winning streak to 26-0 on Saturday, as he reached the Serbian Open clay court final after his semifinal opponent Janko Tipsarevic withdrew with a thigh injury. 

Writing on his Facebook page, Djokovic said: "Janko had to pull out from tonight's semi-final match because of a muscle injury. I sincerely hope he will manage to recover for the rest of the clay court season. I will try to get the title back where it belongs and that is Serbia." 

The 23-year-old will be chasing his fifth title of season on Sunday. 

Standing in his way is the Spaniard Feliciano Lopez who beat the Italian Filippo Volandri 7-6 (7-3) 6-2 in his semifinal. 

The reigning Australian Open champion will take an unblemished 3-0 career lead into the clash with the left-handed Lopez, who is currently ranked No.37 in the world. 

The Spaniard is looking forward to the challenge. 

"I've already won four matches this week. My confidence is really high at the moment and I feel great to play against Novak. I know it's going to be tough; he's been the best player this year. It will be a great experience," Lopez said, AFP reported. 

Meanwhile, at the Estoril Open in Portugal, Argentina's Juan Martin del Potro defeated Pablo Cuevas 6-2 7-6 (8-6) in Saturday's semifinal. 

Del Potro took one hour and 49 minutes to overcome the Uruguayan breaking Cuevas's serve in the first game helping him establish an 4-2 lead when rain intervened. 
When was the semifinal for the Estoril Open?
Saturday