Derbyshire built on a defiant last-wicket stand with six wickets to check Middlesex's progress with the bat on day two at Lord's.
Despite a fine knock of 68 by Sam Robson the hosts reached stumps on 179-6, meaning they still trail their Division One rivals by 52.
The situation could have been even better for the top-flight new boys, who drew their rain-hit opening fixture against reigning champions Warwickshire, had they not missed several chances in the field.
Derbyshire's day had begun with them at the crease, Tim Groenewald and Mark Turner carrying their 10th-wicket partnership on to 50 before the former was caught behind for 25 off Tim Murtagh.
Although they did drop former skipper Chris Rogers on 13, the Australian was unable to make his old employers pay as he fell lbw to Groenewald just three runs later.
Robson, who was reprieved at third slip by visiting captain Wayne Madsen on 22, and Joe Denly added 50 for the second wicket until Jon Clare ended the stand by dismissing Denly for 34.
Middlesex were then wobbling at 90-4 when Dawid Malan and Neil Dexter both fell cheaply just before tea.
A heavy burst of rain stalled Derbyshire's progress and they had to wait until the 17th over after the resumption for a fifth breakthrough, Robson edging Clare to first slip.
John Simpson departed in the next over to Durston's off-spin but Ollie Rayner, who moved on to 16 not out after getting a life from wicketkeeper Tom Poynton, and Gareth Berg (27 not out) saw Middlesex to the close.