The top-seeded Swiss did not face a break point on serve during the one-hour match, as he improved to a 15-0 ATP Head to Head record against the 33-year-old Finn. He also served nine aces while Nieminen had none.
"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."
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.
Rafael Nadal - 329
David Ferrer - 294
Nicolas Almagro - 252
Tommy Robredo - 251
Juan Monaco - 220
Albert Montanes - 202
Roger Federer - 200
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 planned on making good use of his day off Thursday.
"Tomorrow I have a day off and I will enjoy and do a sightseeing trip by boat on the Bosphorus to see some more of this beautiful city," he said.
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).
Date: 29th April 2015, Source: ATP and AFP