(CNN) -- Novak Djokovic duly secured his 26th straight win since the start of the season with a 6-3 6-2 victory win over Slovenia's Blaz Kavcic Friday in the Serbia Open.
Djokovic was playing his second match of the clay court season in his home tournament and was scarcely troubled as he earned a semifinal match against compatriot Janko Tipsarevic.
The world number two closed out victory in one hour 25 minutes as he chases his fifth tournament win of the year on the ATP Tour.
Seventh seed Tipsarevic had to battle for over two and a half hours to see off the challenge of India's Somdev Dewarman 6-3 3-6 6-4.
The 26-year-old from Belgrade native made the crucial break in the fourth game of the decider and staved off a break back point before sealing victory.
Spaniard Feliciano Lopez beat compatriot and fourth seed Albert Montanes 6-4 6-4 to reach his first ATP semifinal of the year.
He will play Italy's Filippo Volandri who defeated Spaniard Marcel Granollers 6-2 6-4.
At the Estoril Open, Argentina's Juan Martin del Potro continued his successful return after wrist injury with a straight sets 6-4 7-5 win over top seed and world number five Robin Soderling.
The match was delayed for several hours with del Potro a set up but 4-1 down in the the second, but he returned to polish off victory in just over two hours, his fourth straight over the Swede.
Another player returning to form after wrist problems is former world number three Nikolay Davydenko, who saw off Croatia's Marin Cilic 7-5 6-3 in the quarterfinals of the BMW Open in Munich.
It is the best showing for the seventh-seeded Russian since being beaten in the Doha final in January by Roger Federer.