The Millers put to rest a 5-1 defeat in the corresponding fixture at Christie Park last season with a fine performance to make it three wins from three in the opening week of the new season, while Morecambe were left still searching for their first victory of the new campaign.
It was the visitors' full-back Mark Lynch who produced the most telling moments of the game with two stunning goals.
After firing his side into an early lead with a superb left-footed curler from the edge of the box after just eight minutes, he repeated the feat in the final minute of the game with another looping effort to blunt any hopes Morecambe may have had of a late comeback.
The former Yeovil right-back opened his account when he cut in from the right wing and spectacularly curled home a stunner from 25 yards.
Morecambe tried to counter and summer signing Neil Wainwright saw a looping header from Garry Hunter's cross land on the roof of the net, while Rene Howe sent one into the side-netting after a sharp turn in the box.
The excellent Reuben Reid looked set to break through the Morecambe defence to make it 2-0 before a vital late tackle from Andy Parrish denied him a run on goal, but he was not to be denied for long as he began the move that led to Rotherham's second five minutes before the break.
Reid found Mark Hudson on the edge of the box and the midfielder cleverly played in Ryan Taylor, who picked his spot and scored past Barry Roche.
Morecambe Sammy McIlroy threw Wayne Curtis on for the ineffective Fraser McLachlan after the break and the home side looked more lively.
The Shrimps almost hit back instantly when a Danny Adams free-kick was just too high for Jim Bentley and Matty Blinkhorn was denied by Andy Warrington at full stretch.
Hunter then volleyed a shot wide before the home side were handed a lifeline with Wainwright nipped in at the far post to volley home a deep cross from Curtis.
But any hopes of a Morecambe comeback were dashed when Lynch scored with another fine curler in the final minute to shatter the Shrimps.