Sheffield United’s hopes of reaching the play-offs were dealt another blow as they were beaten by Millwall.
Chris Taylor scored the only goal of the game as the hosts, in fifth, stretched their lead over Nigel Adkins’ 12th placed team to 10 points.
Deservedly trailing at half-time, the visitors improved after the break but were unable to drag themselves level.
If Neil Harris had feared the departure of Jed Wallace would undermine his team’s promotion push then his replacement, Taylor, quickly put the manager’s mind to rest.
The winger, signed on loan from Blackburn Rovers after Wallace was recalled by Wolverhampton Wanderers, rifled home beyond a helpless George Long after only two minutes of this afternoon’s pivotal League One contest.
If the sight of Taylor converting unmarked inside the penalty area did not cause Adkins enough concern, then watching Alex Baptiste succumb to injury during the opening skirmishes of the second-half did nothing to improve his mood.
The defender who has impressed since arriving on a temporary basis from Middlesbrough earlier this month hobbled off with what appeared to be a knee problem.
Taylor, embarking upon his second spell at The Den, pounced following an incisive move involving Ben Thompson, Steve Morison and Jimmy Abdou. The latter failed to get a touch on the ball when Morison swept a low centre across the box but his presence did help it reach the 29-year-old who duly pounced.
Adkins has placed great emphasis on the importance of establishing a settled starting 11 in recent months but a number of issues, including the return to fitness of Florent Cuvelier and Chris Basham, persuaded him to make changes here.
But Taylor’s early goal meant the manager’s best-laid plans were wrecked before his players had even broken sweat. The defending which allowed the winger to celebrate his return to Millwall with a goal was positively woeful. And, when Lee Gregory went close after poking the ball past the advancing George Long, United’s predicament nearly became even worse.
This match, with the hosts producing some thunderous challenges in midfield, was now all about heart and desire rather than tactics.
Long showed plenty - smothering shots from Lee Gregory and Steve Morison as Millwall threatened to extend their advantage - but his efforts proved in vain.
Conor Sammon, preferred in attack to Che Adams, served notice United were not prepared to surrender without a fight by leaving Mark Beevers on the seat of his pants as they contested a ball towards the corner flag while Alex Baptiste, showing a deft touch for a centre-half, surprisingly took an altogether different approach. His angled pass midway through the opening period, released John Brayford but the wing-back’s cross towards Billy Sharp was blocked.
Long impressed with two fine saves - denying both Gregory and Morison - in the space of a minute before United finally established a foothold of sorts just before the break. Ryan Flynn’s corner was inches away from being turned home by a combination of Sammon and Sharp while Done finally began to enjoy some space along the flank.
Baptiste’s exit forced Adkins to reshuffle a back three which had at times struggled to keep Millwall at arms length. Nevertheless, a decent period of pressure ensured it was not subjected to an immediate examination. Indeed, had Sammon been able to find Sharp after darting clear soon after the restart, United would almost certainly have drawn level. Brayford and Ryan Flynn both saw shots blocked in quick succession.
Sharp also went close at the near post as United searched for an equaliser. But it did not come.
Millwall: Archer, Martin, Gregory (O’Brien 83), Beevers, Webster, Ferguson (Upson 90), Taylor, Morison, Thompson, Abdou, Romeo. Not used: Forde, Edwards, Williams, Onyedinma, Nelson.
Sheffield United: Long, Brayford, Basham, Flynn, Sharp, Done, Sammon (Adams 72), Baptiste (McEveley 48), Cuvelier (Coutts 67), Edgar, Hammond. Not used: Howard, Calvert-Lewin, Whiteman, Kelly.
Referee: Oliver Langford (West Midlands)