Promoted to number three, Iyer hit the Bengal bowlers all over the park with four sixes and 16 boundaries in his 175-ball knock en route to his first century as Mumbai ended the day at a commanding 306 for four.
His four sixes included two against Veer Pratap and one off pacer Ashok Dinda as the youngster did not give Bengal bowlers any chance. Poor fielding too was a letdown for Bengal.
While Iyer was a delight to watch as he showed no mercy to an out-and-out seam attack from Bengal, hitting them all over the park, Nayar rotated the strike cleverly as the duo scored briskly at 4.69 per over in the association that began in the post lunch session.
It indeed helped their cause as the opening pair of Aditya Tare and Akhil Herwadkar began the proceedings at a snail's pace, scoring at less than two per over.
Mumbai could only seize the momentum in the second session of the day after the dismissal of Tare who consumed 105 balls for his 24 that also included two reprieves -- while on 4 and then on 23 -- in the slip cordon and both by a butterfingered Sudeep Chatterjee.