THE scoreline sounds harsh, as the Linnets were in the tie at 2-1 until the 63rd minute.
At that point the game turned when Glen Fuff was sent off for handball, and which gave Ilkeston a penalty, just after two penalty appeals for challenges on Carl Holmes were turned down.
As the Robins expertly exploited the man advantage, Lynn's defence fell to pieces.
Defender Mark Burrows marked his debut with a goal in first half injury-time to keep Lynn interested, but they frequently played a long ball game which suited Ilkeston down to the ground.
The Linnets started each half the better side but instead of keeping the ball down and using their wing-backs, they pumped too many balls up to the ineffective Lee Stephenson and Paul Watts.
Watts could not win a header against defenders much taller than him.
It was all different at the start of the game, which underdogs Lynn bossed, with wing-backs Wayne Anderson and David Staff threatening.
However, they could not force a save from the keeper, Lee Stephenson having an effort blocked by defender James Whitehead.
Then from the first quarter hour Ilkeston came into the game as they looked strong and The Walks outfit looked jittery at set-pieces.
Keeper Dean Greygoose tipped an Ian Robinson shot around the post and Staff cleared off the line from a header by former Lynn player Emeka Nwadike before the hosts opened the scoring in the 26th minute.
Barry Woolley was unmarked to head home from close range. The Robins continued to pressure and got their second goal three minutes later, Leon Kelly also heading in unmarked from a cross.
From the kick-off Holmes hit the base of the post, then Staff's 20-yard drive was tipped over by keeper Matt Nurse.
Lynn got their reward when Stephenson horrendously miskicked Holmes' ball dinked over the defence, but it fell to Burrows who tapped in.
Early in the second half Holmes had two penalty appeals turned down.
But then Greygoose came out and missed the ball, an overhead kick hit Fuff's arm and a harsh decision saw the Lynn skipper become the 100th Lynn player to be sent off since the war.
Paul Kiely converted the resulting penalty, although Greygoose touched the ball onto the post, and into the net.
Three goals in the final five minutes killed off Lynn, the first against nine men as Anderson was off with cramp.
Greygoose again got a hand to sub Richard Mitchell's chest-down and shot, in the 89th minute Kiely bagged his second which looked offside, and in stoppage time Lynn allowed full-back Whitehead to run around the edge of the box unchallenged and he rifled into the top corner.
Lynn: Greygoose, Anderson, Staff, Burrows, Fuff, Johnson, Weston (Cowling 62), Raynor, Watts (Bacon 70), Stephenson, Holmes (Blake 81) Subs not used: Gowshall, Dobrowolski. Booking: Holmes (58, dissent), Sent Off: Fuff (63, handball)
Ilkeston: M. Nurse, J. Whitehead, J. Atkinson, S. Dundas (S. Coates 58), B. Woolley, S. Coleman, R. Ford (T. Brown 77), I. Robinson, L. Kelly (R. Mitchell 51), P Kiely E. Nwadike. Not used: A. Foster, M. Smith.
Referee: P.S. Barston.