Safin is working his way back up the rankings

Finland's Nieminen broke Safin's serve twice en route to taking the first set, but the Russian hit back in the sixth game of the second for a 4-2 lead.

Safin broke again in the first game of the third and saved break points in the fourth and sixth games before breaking in the seventh to clinch victory.

The ex-world number one will next meet Kristof Vliegen or Paul-Henri Mathieu.

Safin beat Mathieu last weekend in the decisive singles rubber to put Russia into the Davis Cup semi-finals at the expense of France.

Also on Sunday, Frenchman Julien Benneteau, a French Open quarter-finalist last year, struggled through against Monaco's Benjamin Balleret 7-5 5-7 6-2.

World No 1 Roger Federer and title-holder Rafael Nadal, who is on a record 62-match winning streak on clay, have byes into the second round and will not be in action until Tuesday.