Charlie Cresswell came off the bench to set Millwall on their way to ending a run of three straight defeats with a 2-0 victory over Cardiff at The Den.
It was the centre-back's third goal of the season - following up his opening-day double against Stoke - while it also softened the blow of the Lions losing their captain Shaun Hutchinson to injury, with Benik Afobe's late strike making sure of the points.
However, it was another frustrating day for the Bluebirds, who struck the woodwork twice in south London as their winless run in the Sky Bet Championship was extended to five games.
Millwall named deadline-day signing Callum Styles in their midfield, although Cardiff's Callum Robinson was made to wait slightly for his debut as he was named on the bench.
There were a couple of early efforts from distance, with Zian Flemming testing Bluebirds goalkeeper Ryan Allsop before Jaden Philogene fired comfortably over the top.
Philogene then had the game's first big chance after 14 minutes when Max Watters chipped the ball in towards the Aston Villa loanee, who could only head wide despite getting in ahead of the defence.
The Lions had a decent opening themselves shortly after as Andreas Voglsammer laid the ball off for Flemming, who bent a low effort wide of the far post.
That preceded a good spell from the hosts, which included Murray Wallace shooting wide of the near post after a marauding run down the left.
George Saville then had a header from Jamie Shackleton's cross saved by Allsop before Cardiff came within a whisker of going ahead themselves when Sheyi Ojo prodded Niels Nkounkou's low ball against a post from point-blank range.
Millwall lost Hutchinson to what looked like a groin strain early in the second half and he was replaced by Cresswell.
Cardiff were then cursing their luck again just after the hour mark when half-time substitute Mark Harris cut inside from the left before his placed effort ran against the far post.
The Lions made the most of their good fortune by taking the lead in the 63rd minute when Scott Malone, only just on himself, played in a corner that Cresswell rose to meet and head home.
Another of the hosts' substitutes, Tyler Burey, tried to double his side's advantage when he tried his luck from distance, but Allsop saved easily.
Nkounkou continued to look lively on the left and he almost forced an equaliser when his low shot had to be pushed away by Millwall keeper Bartosz Bialkowski at his near post.
The hosts' victory was then sealed by Afobe in the final minute as he ran on to a long ball before beating Nkounkou and lifting the ball over Allsop with a neat finish.
Millwall: Białkowski, Wallace, Hutchinson © (Cresswell 48’), Cooper, Mitchell, Bradshaw (Afobe 62’), Flemming (Honeyman 89’), Shackleton, Styles, Voglsammer (Burey 62’), Saville (Malone 62’). Subs not used: Long, McNamara.
Cardiff City: Allsop, Romeo, Kipré, Ng, Nkounkou, Wintle ©, Rinomhota, Sawyers (Ralls 69’), Ojo (Harris 45’), Philogene (Whyte 69’), Watters (Robinson 45’). Subs not used: Alnwick, Simpson, Sang.