Ryan Leonard's stunning first-half strike helped Millwall edge past Preston 2-0 in a game of attrition at Deepdale.
The 33-year-old right-back scored his first Championship goal of the season with a delightful curling strike in the 29th minute and substitute Luke Cundle sealed the win in second-half stoppage time.
It is a result that keeps Alex Neil's team well in contention for an automatic promotion spot while also pouring more cold water on the club he used to manage, as the Lilywhites' play-off ambitions fade further away.
A scrappy opening had its first real shot in anger as Brad Potts thumped a 14th-minute effort straight into the arms of Anthony Patterson from the edge of the box, having run on to Lewis Dobbin's line-splitting pass.
The Lions roared back in the 20th minute as Josh Coburn's close-range header bounced off the crossbar via a Preston body as the hosts struggled to clear their lines from Jake Cooper's initial cross.
Shortly after Andrija Vukcevic found Daniel Jebbison with an outswinging cross and the North End forward planted a firm header well wide.
Against the scruffy nature of the match, Millwall's opener was a thing of beauty as right-back Leonard caressed the ball across Dai Cornell deliciously from just inside the box with Casper De Norre teeing him up.
They should have doubled their lead in the 39th minute as Camiel Neghli dragged wide from close range, stuck between a shot and a pass to Coburn who would have had a tap-in, after De Norre cut Preston's defence wide open.
The visitors twice went close again on the stroke of half time as Cooper volleyed Femi Azeez's corner towards the corner and Brad Potts had to be alert to clear off the line before Cornell made a sensational diving save to tip Neghli's 25-yard strike round the post.
Neil's men set up to frustrate after the interval and the hosts struggled to find any rhythm in their play for the most part.
Callum Lang did burst in behind the steely defensive Millwall in the 69th minute but he was unable to make it count, seeing his shot deflect comfortably into the arms of Patterson.
As time went on, spaces opened up for the visitors to seal the game with Azeez and Coburn both firing wide from just outside the box.
Azeez then nearly killed the game off with a wonderful slaloming 82nd-minute solo effort, only to be denied by an advancing Cornell.
That looked to be that until the excellent Azeez found Cundle at the back post two minutes into stoppage time with an inch-perfect cross and the 23-year-old tapped into an empty net to wrap up three points.
Preston's Paul Heckingbottom:
"The better team won in terms of the chances created. I've got no complaints. The game had no surprises. They're a very difficult team to play against and arguably they do the basics better than anyone in this league. Their experienced players know what their strengths are and they play to those strengths.
"I've only seen moments back in the game where we got so far, we outnumbered them behind their midfield, getting [into] good [situations] and we actually outnumbered them in the box as well. The initial thoughts from those moments are that a little bit more quality in those areas, or sometimes pure luck, was the difference."
Millwall's Alex Neil:
"I think it was always going to be a tough game. I think if you take it in contrast to the Birmingham game, which was very tactical, very much a high-press, because the difference here was the pitch.
"I feel sorry for Preston in the fact that it's really difficult to get the ball moving on that. It basically becomes a second-ball game and [to] make sure you defend well, get ahead of your man, [win] duels. It doesn't make for good viewing if I'm being honest.
"However, it's the same for both teams so we don't want to use that as an excuse. We spoke about making sure that, if you want to be successful at this level, you can win games in a variety of different ways.
"We spoke about keeping the ball in front of them because we know they want to get down the sides and get in behind but if you can keep them in front of you then they need to make passes and then what happens is they start to open their shape up and we have spaces to break into and that's how we nick it."
