By Gabriel Tan
The Warriors have now picked up just one point from their last three games after falling to substitute Andrew Tan's 69th-minute winner.
Bok's charges looked extremely lacklustre throughout the game and largely failed to break down the Tigers' well-organised structure, and the SAFFC coach admits he is finding it tough to lift the players' spirits at the moment.
"Right now, we are down in morale and confidence and it is eating into the team," Bok said after the game.
"We tried to do something about it but at the moment it's not working. It's not easy to keep the morale up.
"You are dealing with people with different characters and personalities - you never know what they have on their minds. It's not easy but I will just have to try my best to bring the morale up."
Most of SAFFC's woes this season have stemmed from their defensive inadequacies, with their attack still one of the most lethal in the league at the moment.
However, they failed to muster any significant goalscoring opportunities on Thursday, something Bok believes their opponents deserve credit for.
"In the first half we were a bit better. In the second half, other than one shot from Kari [Mislav Karoglan], I don't think we created that much.
"I think they [Balestier] are a very disciplined lot, very organised and they put their bodies on the line.
"They nullified our attack very well. They stuck to their plan to get men behind the ball and there was very little space for us to play.
"They hit on the break and we tried to deal with that - only on one occasion did we fail to do so."
And while the Warriors remain the S.League's most successful club with eight league titles, four of which came under Bok's reign, he insists the team have now entered a new rebuilding phase.
"That era is gone," Bok asserted. "We are trying to build a new team now and it's taking longer than we though after [the last title] in 2009, so we still have to work on it.
"We may inject some new young players in the starting lineup; maybe that will work."
SAFFC are back in action next Sunday when they entertain Hougang United at the Choa Chu Kang Stadium.