By Gabriel Tan
Tatsuro Inui netted the only goal of the game in the 35th minute from the spot to hand his side the slimmest of advantages, after Nurullah Hussein had been harshly penalised for handball inside the penalty box.
However, Gombak did come back strongly in the second half and had plenty of chances to equalise, only to be denied by an inspired display from Warriors custodian Shahril Jantan.
While he admitted his side struggled to get going after the break, Bok insists he is pleased with their overall performance.
"A one-goal lead is still a lead," he said. "Although he would have liked to have another one.
"We were better in the first half and created more chances, but the second half was a little scrappy. But we're still in the lead and we'll see what happens on Saturday [in the second leg]."
The four-time Great Eastern-YEO's S.League-winning tactician conceded Shahril had saved SAFFC on the night, and has called for his side to show plenty of desire in the second leg at the Jurong West Stadium.
"He [Shahril] definitely kept us in the lead with two or three good saves," Bok added. "Hopefully he can keep his form because he saved us tonight [Wednesday].
"We will need to show desire on Saturday. The job's not done yet and there's still 90 minutes to play.
"We'll try to defend well but also create chances."
Gombak coach K. Balagumaran was extremely proud of his side in the way they had outplayed their more-illustrious opponents, and believed a questionable penalty decision had been the only difference between the two teams.
"It all went right except for the penalty," he said. "Nurullah said he was jumping for a header when the ball struck his arm.
"I have to say the referee was outrageous tonight [Wednesday] but let's leave it at that.
"The boys were excellent and we dominated the second half. SAFFC were conservative and were focused on holding on to the lead.
"If we keen on playing like this, we definitely have a chance [on Saturday]."
SAFFC are currently seventh in the S.League, while Gombak are a point behind in eighth place.