Millwall condemned Reading to their fourth successive Championship defeat as Benik Afobe’s goal was enough to win three points for the hosts at the Den.
With an absent manager and 12 first-team players out injured, the Royals slump in form continued as they dropped down to 17th after Afobe’s 71st winner.
With manager Veljko Paunovic in isolation after testing positive for covid-19, assistant manager Marko Mitorovic took charge.
The Royals made two changes from their weekend’s defeat to Bournemouth as Tyler Ashcroft came in for Danny Drinkwater and Tom Holmes replaced Andy Yiadom.
There was an ominous start for the Royals as Millwall’s free-kick specialist Jed Wallace had the chance to give them the lead with a well positioned set-piece.
However, Reading goalkeeper Luke Southwood made a smart stop as he flew to his right to tip the ball behind for a corner.
Southwood then came out confidently to collect a swinging cross from Wallace as the Millwall midfielder looked to pick out one of his teammates in the middle.
Former Royals loanee Benik Afobe had a sight of goal when the ball was pulled back for him invitingly in the box but he snatched at his shot that flew high into the stands.
Reading began to grow into the half and show some attacking intent when John Swift and Ovie Ejaria linked up on the left.
Ejaria found left-back Baba Rahman out wide who used his strength to work his way into the box but as he tried to pick out George Puscas, Millwall goalkeeper Bartosz Bialkowski grabbed the cross.
Puscas looked in a tenacious mood working up top for the team as he turned away from his marker and found Swift in the middle, who chested the ball down and hit a shot thatr was well blocked.
Swift then had another attempt at goal when he cut it from the left quickly onto his right foot but hit his effort high and wide.
Reading goalkeeper Southwood continued to look confident between the sticks in his 10th consecutive league appearance as he rushed out at the feet of Afobe to close his angle down.
The Royals had the ball in the net after half an hour only to be denied by the offside flag.
Ejaria threaded a ball through to find the run of Puscas, who rounded the keeper and slotted into the empty net, but he was flagged offside well before his finish.
Maikel Kienftenbeld picked up the first yellow card of the game for the hosts after making three three consecutive fouls.
Tyrell Ashcroft impressed in his first 45 minutes of Championship action as he swung in a brilliant cross towards Puscas, but a Millwall defender got a toe on the ball to take it away from the path of the Romanian.
Reading enjoyed a good spell towards the end of the half as they piled the pressure on the home side.
Ejaria got into the box on a couple of occasions with his trickery but former Royals graduate Jake Cooper made a vital block for the Lions.
Ejaria then came even closer as he twisted past a defender before his low shot flashed across the goal and past the post.
A chance came the way of Millwall early in the second-half for George Saville but his shot had the sting taken out of it by the block of Liam Moore before Southwood collected the loose ball.
Millwall built an impressive spell of possession and pressure in the opening 15 minutes of the half as Ryan Leonard’s cross from the right almost caught out Southwood, but the frame of the goal came to his rescue.
Wallace then went close as his shot fizzed just wide of the far post, before Southwood made a save from Mason Bennett.
After a spell of sustained attacks, Millwall eventually broke the deadlock in the 71st minute as Afobe latched onto Leanoard’s low cross in the box and tapped in from close range.
The hosts could have extended their lead just three minutes later when Malone rushed on to a cross and volleyed an effort towards goal that just evaded the top right hand corner.
Reading’s best chance of the half fell to Swift in the 77th minute as a cross dropped at his feet, he took a touch to set himself but missed the target as he tried to pick out the top corner.
The first change of the night for the away side saw Jahmari Clarke replace Puscas.
Trying to force the issue to find a leveller in the final 10 minutes as 17-year-old Mamadi Camara replaced Ejaria.
But they couldn’t find an opening to stop their losing run as the final chance came when Swift hit a tame free-kick into the Millwall wall.
Reading are on the road again this weekend when they face Birmingham City on Saturday.
Millwall: Bialkowski, Cooper, Hutchingson, Saville, Leonard, Kietfenbeld, Mitchell, M Wallace, J Wallace, Afobe, Smith
Subs: Long McNamara, Bradshaw, Malone, Ojo, Pearce, Bennett
Reading: Southwood, Holmes, Moore (c), Dann, Rahman, Ashcroft, Laurent, Dele-Bashiru, Swift, Ejaria, Puscas
Subs: Rafael, Camara, Ehibhationham, Osorio, Clarke, Samuels, Abrefa
Goals: Afobe 71′
