Nigel Adkins insists the fight must go, despite Wednesday's loss in front of the Sky cameras at Southend.
Dean Hammond cancelled out Tyrone Barnett's first-half opener, but goals from David Worrall and Jack Payne ensured all three points went the way of Phil Brown's Shrimpers, despite United creating a number of clear cut chances.
Speaking in the aftermath of the loss at Roots Hall, Adkins commented: "We created opportunities and moved the ball quickly at times; we were disappointed with the first goal we conceded, but reacted positively and got a deserved equaliser.
"Then we start the second-half on the front foot and we had chances before they score after we give the ball away in a bad area.
"Towards the end, we threw caution to the wind in a bid to get on level terms and for their third goal we have hit the post from the corner before they break. We still had two versus one, but Payne, to be fair has finished it very well."
The defeat leaves United in 13th place in Sky Bet League One and nine points off the top six with seven games remaining, but the Gaffer is refusing to accept the race for a play-off position is over.
He added: "We needed to win the game and we had our chances to do so. Billy Sharp and Che Adams missed chances, but linked up well and our play was good at times, but the result is disappointing and very annoying.
"We had some good performances, but ultimately it doesn't matter because we haven't won the game and that is what we endeavoured to do.
"It is a quick turnaround ahead of the weekend, but it's down to me to rally everyone for Walsall on Saturday, you will never hear me give up, all we can do is look to win the next game."