Conceding two quick-fire goals in the second half made it tricky for the Shrimps, admits Derek Adams.
David McGoldrick opened the scoring just before the break on 45 minutes from a free kick before adding a second and third respectively moments after half time.
James Collins stepped up to convert the hosts’ second penalty of the afternoon before Jason Knight completed the scoring.
“Our first half performance was very good, the second half we couldn’t do much about it,” Adams said.
“We were 3-0 down quite quickly into that second half and Derby, at that stage, their tales were up; they’re at home, the home crowd are with them.
“We had moments in the first half where we got into their final third with Adam Mayor, Arthur Gnahoua, [Dan] Crowley and [Cole] Stockton, but we just weren’t able to get the better of them today.”
Attention turns to the visit of Forest Green Rovers on Saturday 11 February who, at the time of writing, find themselves bottom of the Sky Bet League One table on 21 points, six behind Morecambe.
While Adams acknowledges every game in a season is big, his side will be eager to extend their recent home form.
He continued: “Games are always big, it doesn’t matter what time of the season it is.
“We’ve put a home run of form together that is eight undefeated, and we want to continue that.
“We kept them [Derby] at bay at home, away from home we found it difficult, it’s difficult coming to these venues and trying to get results.”