Liam Feeney's first-half goal was enough for Championship side Millwall to reach the FA Cup fourth round at the expense of Preston.
Preston's Paul Huntington missed a decent chance before Feeney drilled in a low right-wing cross from Adam Smith.
The Lions had a chance to double their lead when Darius Henderson was clean through, but he was denied by David Buchanan's last-ditch challenge.
Other chances were rare as Millwall clinched victory in a uninspiring tie.
Millwall, who reached the 2004 final, started brightly at the New Den and created the first real chance of the match through Dany N'Guessan, whose shot at goal was blocked by Chris Robertson.
Kenny Jackett's men continued to enjoy the majority of possession in the opening 15 minutes, but struggled to carve out any meaningful goalscoring opportunities.
Henderson's left-footed effort from 12 yards was deflected onto the Preston crossbar, before Feeney broke the deadlock shortly after the half-hour mark.
Preston's first-half chances were limited to Huntington's effort when he swivelled to meet Jack King's flick but could only fire over the crossbar.
Millwall continued to press after the break and a 52nd-minute strike by Henderson from inside the area forced Steve Simonsen into an impressive diving save.
Two-time FA Cup winners North End tried to battle their way back into the match as it approached the 70-minute mark but, despite enjoying a greater share of possession, were unable to create any significant chances.
Substitute Graham Cummins went close to stealing a replay when his late six-yard effort was parried behind for a corner by Millwall stopper David Forde.
But Millwall saw the game out as Preston, who lifted the trophy in 1889 and 1938, failed to reach the fourth round for the fourth time in five years.
Millwall manager Kenny Jackett: "In the first half we played very well, and created some great chances at the start of the second half.
"We needed to get more goals up really to make it comfortable. We were quite dominant in the first half and had to defend for the last half an hour, which was frustrating.
"We hope to get a big draw in the next round for many reasons, and the prize money for today will certainly help. But it's not a direct translation to money I have to spend on the pitch."
Preston manager Graham Westley: "We feel we put in a good enough display to get the goal that would earn us the replay, but things are as they are unfortunately.
"When you go in one nil down at half time you're always trying to look to make a difference to the game and if you can get a grip in midfield, which we did second half, then you have a platform to build on.
"We try to look at the team performance rather than individuals, and from our point of view it was never going to be easy to come to their patch as they're flying high at the moment."