An early break for Nadal in the very first game of the match secured him the first set.
Nadal, watched on by a 3 time Monte Carlo Champion Bjorn Borg, raised his level in the second set and broke Nieminen three times as he stormed to victory.
The world no.2 will play Mikhail Kukushkin of Kazakhstan next, who defeated Italy´s Filippo Volandri 7-6 (8) 2-6 6-2.
Nadal is aiming to win this very popular Master Tournament for the 8th time. He beat David Ferrer in last year’s final.
Also through to the next round is the 8th seed Spaniard Nicolas Almagro, who ousted the Italian wild card holder Potito Starace 7-6 (3) 6-1 and the Swiss Stanislas Wawrinka, who overcame Pablo Andujar of Spain 7-5 6-3.