Top-seeded Roger Federer gave a demonstration of his service skills as he beat Jarkko Nieminen 6-2, 7-5 on Wednesday to reach the quarter-finals of the inaugural Istanbul Open clay-court tournament.The top-seeded Swiss did not face a break point on serve during the one-hour match, as he improved to a 15-0 FedEx ATP Head2Head record against the 33-year-old Finn. "I'm happy that I won my first match ever in Turkey," he said. "In the second set Jarkko started playing better and I'm happy that I managed to close the match."Mostly, the games are not played on clay in the evenings. Because the soil is exposed to the humidity during the evening time. Long matches on clay cause the ball to get weight. I preferred to play agressively and shorten the game tonight. I think the ball rebounded too much. My rival, Nieminen, knew well how to play on clay. I followed some of his matches. I'm at the beginning of the clay season. I hope I have a good season." On the question of whether he prefers to play against Grigor Dimitrov and what he thinks about him, Federer responded cautiously, "I hope I can advance to the final. And I hope he can too. I like his playing style. He is a very athletic, watchable player. He is also a good sport off of the court. It will be not so easy to advance to final for him too. He hasn't been able to give many good performances in his last few games. He feels a little pressure,"He became the seventh active player to reach the 200 clay-court match wins milestone, and the fourth to win 200 or more tour-level matches on both hard and clay courts, joining Rafael Nadal, David Ferrer and Tommy Robredo.Federer, who is looking to win his 11th clay-court title this week, will face Daniel Gimeno-Traver in the quarter-finals, but first, he made good use of his day off yesterday. "I have a day off and I will enjoy it and do a sightseeing trip by boat on the Bosporus to see some more of this beautiful city," he said after the match.Earlier Wednesday, Gimeno-Traver fired five aces past sixth seed Mikhail Kukushkin in a 6-3, 6-3 win, his third in four meetings against the Kazakh. The in-form Spaniard is 7-2 in his past two tournaments, highlighted by a runner-up finish at the Grand Prix Hassan II (l. to Klizan).Fourth-seeded Santiago Giraldo of Colombia beat Russian Andrey Rublev 6-4, 1-6, 6-3 to reach the quarterfinals of the inaugural ıstanbul Open on Wednesday, while Spaniard Daniel Gimeno-Traver upset sixth-seeded Kazakh Mikhail Kukushkin 6-3, 6-3 to set up a potential match against Roger Federer.Separately, world No. 1 Novak Djokovic will miss next week's Madrid Masters for the second straight year, with tournament officials confirming his decision. Djokovic has expressed worries about burning himself out on clay before the start of the French Open in less than a month.The Serb already owns four titles this season and has a healthy lead of well over 5,000 rankings points over No. 2 Roger Federer, playing this week in Istanbul.Djokovic, the only man to win titles at the first three Masters events in a season (Indian Wells, Miami and Monte Carlo), won the Monte Carlo title to start the clay season. He also missed Madrid in 2014 due to a wrist injury, returning a week later to win Rome over Rafael Nadal.