Rafael Nadal emerged a 6-4, 6-3 winner over Jarkko Nieminen with no obvious discomfort to his troublesome left knee as the Spaniard began his quest for a record eighth title at the Monte Carlo Masters. Nadal, now 40-1 at the venue where he lost his only match in 2003, won his 38th straight match in the principality as he overcame stubborn resistance from the 48th-ranked Finn, who claimed the Sydney title in January. Nadal, who required two weeks of knee treatment after failing to play his Miami semi-final match due to knee pain last month, has not lifted a trophy since the French Open 10 months ago. "I played a really normal match, nothing special -- nothing very bad, but nothing very good," said Nadal, who faces Kazakh qualifier Mikhail Kukushkin on Thursday. "It was the first match on clay after a long time, and the first match after 15 days without touching a racquet. "The important thing was that I won in straight sets. Tomorrow I have another chance to keep improving, and that's what I'm going to try. "You need days to see how all the sensations improve -- the knees, the tennis, everything. When you stop for 15 days without practice, your body loses a little bit of the performance." The second seed joined world number one Novak Djokovic in moving through a clay-season opener in straight sets on a cloudy day on the Mediterranean coast. Djokovic began with a 6-1, 6-4, victory over Andreas Seppi, taking a 5-0 lead over the 44th-ranked Italian and breaking for an early lead in the second set on the way to his seventh win in their series of encounters. "I served really well when I needed to," said Djokovic. "That's encouraging for the clay, it's good to have a couple of free points there. "I was really focused first set and played it well against a tough, quality opponent who plays good on clay. For the first official match since Roland Garros last year, it was satisfying." The top seed will next play 16th-seeded Ukrainian Alexandr Dolgopolov, who put out new Monte Carlo resident Bernard Tomic of Australia 6-2, 5-7, 6-1. "He's a very talented player, comes up with some shots that are not really typical," said Djokovic of Dolgopolov. "He changes the pace and is very dangerous on clay. I need to be aware and disciplined on the court. I need to try not to be frustrated with the rhythm that he comes up with." There was a shock for fifth seed David Ferrer as the Spaniard went down to Thomaz Bellucci of Brazil 6-3, 6-2. Number six seed Tomas Berdych dismissed Croatian Marin Cilic 7-6 (7/3), 6-1, with Serb number seven Janko Tipsarevic advancing over Spain's Albert Montanes 6-2, 6-3. Number eight seed Nicolas Almagro beat Italian Potito Starace 7-6 (7/3), 6-1, while number nine-seeded Frenchman Gilles Simon won a match that began at the early hour of 10:30 local time, beating Frederico Gil of Portugal 6-3, 6-0. Julien Benneteau registered another French win as he put out 2011 semi-finalist and 15th seed Jurgen Melzer of Austria 6-4, 6-3. Benneteau tackles British third seed Andy Murray in the next round. Kukushkin booked his date with Nadal by beating Italy's Filippo Volandri 7-6 (10/8), 2-6, 6-2 and Switzerland's Stanislas Wawrinka beat Pablo Andujar, the champion in Casablanca last Sunday, 7-5, 6-3.