Horndean’s title chase was hit by a 3-1 defeat to favourites Solent II in national league division two south.
The loss underlined just how much the Deans have missed Norwegian talisman Haakon Lie.
Horndean’s form has dropped off without their powerful outside-attacker who has been unavailable.
Player-coach Nasser Ssemuwemba believes his side cannot afford to lose any more games if they are to challenge leaders Wessex M3.
He said: ‘Sadly for us, you can say that our wheels have started to wobble.
‘However, if you look at a few things over the sets we lost to Solent, we didn’t do what we should have done.
‘It is disappointing again but we need to regroup and come back again.
‘It shows we now need to make up the ground, starting from this weekend.
‘The reality is, if we lose to Southampton on Saturday then our chances of an automatic qualification spot will be gone.’
The Deans began well at the Itchen College court.
They exploited Solent’s fragmented defence with a number of cross-court hits from Damian Roberts and tactical serves from Willard Hans Shongue.
But the home side weathered the storm to win the opening set 25-22.
The Deans got back onto level terms 25-22, thanks to powerful jump serves from man-of-the-match Leandros Tsikras.
However, Solent stormed back to regain the lead 25-16.
And although the Deans fought hard in the fourth set, Solent took it 25-23.
Horndean’s middle-blocker Hans Shongue believes there is still hope in the promotion race.
He said: ‘All is not lost. I know everybody feels low but both Solent and Wessex still have to come to us.
‘If we can get our best players back – playing in their natural positions, then we can beat both teams.
‘We’ve only had six players available for each of the past two matches, and we’ve had to play players out of their usual places.
‘I still believe we can finish top but if that fails to happen then we shall fight for the second spot so as to qualify for the play-offs.’
Horndean face rivals Team Southampton at Highbury College on Saturday (11am).