A siperb goal from Jimmy Spencer gave the Shrimps a vital win at play-off chasing Rotherham.
Spencer strucj with seven minutes to go as he latc`hed on to Kevan Hurst's through ball and produced a superb left foot shot to beat home keeper Andy Warrington to his left hand side.
The Millers started well and teenager Niall Cowperthwaite, making his debut at left back, cleared a Ryan Taylor effort off the line after just three minutes. Two minutes later Nicky Law crossed into a packed box rather than shoot and Morecambe came back into the game after the early pressure.
Phil Jevons forced Andy Warrington into two good saves and Jimmy Spencer tested the Rotherham number one with a fine volley that was heading for the left hand corner. Garry Hunter then headed over from a Spencer cross as the Shrimps produced some threatening monents.
The Millers came back strongly towards the end of the half with Law forcing Roche into a good save and Adam Le Fondre failing to connect from close range when he looked certain to score.
The seocnd half saw Morecambe maintain the pressure while at the other end defend superbly to restrict Le Fondre to only one effort on goal which was superbly blocked by Chris McCready.
After Spencer's late goal the Shrimps were relieved to see an injury time header from Johnny Mullins fly inches wide of the left hand post.
Rotherham: Warrington; Tonge, Mullins, Fenton, Newey; Marshall, Harrison, Bradley, Law; Le Fonde, R Taylor. Subs: Asworth, J Taylor, Brogan, Green, Daley, Henderson, Annerson (GK).
Morecambe: Roche; Parrish, Haining, McCready, Cowperthwaite; Hurst, Drummond, Hunter, Holdsworth, Jevons, Spencer. Subs: Anyon (GK) Wainwright, Wraighte. Carlton, Bentley, Aley.
Ref: S Rushton.