Milwall manager Kenny Jackett has called on his side to bounce back quickly from Saturday's setback after their 3-0 defeat at the hands of Huddersfield.
The Lions have an immediate chance to make amends for the 3-0 defeat when they host Blackburn on Tuesday night.
Millwall's run to the FA Cup semi-final has left them with a backlog of fixtures and, Jackett admits, a few tired legs.
They have three home games in a row against Rovers, Nottingham Forest and Crystal Palace, and still need a couple of points to be sure of avoiding relegation.
Jackett said: "The side lacked energy and sparkle, not necessarily commitment, but certainly sparkle.
"From our point of view we still have four games left and the equation does lie with getting a team that has the energy to get the points we need at home.
"We have to lick our wounds, make sure we get it right and have a freshness and move on again.
"I'm obviously concerned, but we have to look forward and focus on our three home games in a row. We must get over it quickly."
The 39-year-old has revitalised the Adams Park side since being handed the job in November, hauling them from the foot of the Football League to a comfortable mid-table finish.
The winger has pulled on his boots on 19 occasions since taking up the reins but this weekend's match against his former club, his 600th in professional football should he make an appearance, will be his last.
"I'm really, really pleased," he told the club's official website. "I'm honoured, proud and very, very thankful to everyone that has supported me in any way that they have. Everyone has been behind me since day one.
"This is enormous for me and I'm really thankful to everyone who has helped me achieve this. I want to repay the Trust and all the supporters by working so hard and bringing back the glory years. I'll give it my best shot, I promise you.
"The hardest part is making that decision (to retire). Football has been my life for all these years - it's all I've ever done and ever known. I've spoken to people who are close to me and everyone seems to think it's the right thing to do - it's better to go out on a high.
"Thank you to everyone who has ever shouted for me at every club I've played for. It's been a rollercoaster but I wouldn't change any minute of it for anything."
Joint-chairman Don Woodward added: "It's great to secure Gareth's services and we are really looking forward to continuing to work with a young but passionate manager.
"We are very excited to have a natural leader and a great guy managing our football club, hopefully onwards and upwards."
