By Gabriel Tan at the Jurong West Stadium
Gombak went ahead after just seven minutes when French striker Julien Durand rose highest to nod home a corner from Mustaqim Manzur.
However, the Cheetahs fought back strongly in the second half and equalised two minutes after the break through star forward Jordan Webb, before Ante Barac grabbed what proved to be the winner four minutes later when his powerful drive was deflected into the back of the net.
The result was also a bitter pill to swallow for the hosts as they failed to hold on to a lead for the second game running, and were left to rue their inability to convert their dominance into goals.
Just like they did in their last outing against Home United in the Great Eastern-YEO's S.League 11 days ago, the Bulls got off to an extremely bright start and nearly took the lead in the fifth minute when Hafiz Rahim sent an acrobatic volley just wide after Christopher Anderson had flicked a throw-in into his path.
However, there was to be no denying them a couple of minutes later when they opened the scoring after Mustaqim whipped in a pinpoint delivery that was glanced into the far corner by Durand.
Five minutes later, Gombak nearly put their aerial dominance to good use once again when captain Obadin Aikhena sent a header narrowly wide after another good cross from K. Vikraman.
As the half wore on, the hosts really started to dominate proceedings, especially in the middle of the park where anchorman Adrian Dhanaraj was controlling the midfield battle with authority. On the other hand, Hougang struggled to get any sort of passing rhythm going, and largely resorted to aimless long balls from the back by Stanislav Vidakovic.
Durand in particular was looking very lively for the Bulls and he carved open the opposition defence again in the 32nd minute when he went on a terrific dribble past two men, only to see his cut-back cleared by a desperate Syaqir Sulaiman before Hafiz could pounce.
Hougang coach Nenad Bacina spent much of the opening period fuming at his players down the touchline, but whatever he said to them at the interval seemed to work as they came out after the break a different side, and duly equalised in the 47th minute.
In a carbon copy of Gombak's opener, Barac whipped in an excellent corner from the left straight onto the head of Webb, who powered an effort towards goal. Despite some frantic attempts by the Bulls defenders, the ball was adjudged to have crossed the line although Mamadou Diallo prodded the loose ball into the back of the net for good measure.
Four minutes later, Hougang hit the front when Barac picked up possession down the right and cut in on his trusted left foot, before unleashing a ferocious strike that took a wicked deflection of Obadin and left Zaiful Nizam with no chance of keeping out.
Having again seen a lead evaporate before their very eyes, Gombak began to push more men forward in a bid to restore parity. Vikraman came close in the 66th minute when he curled in a cross-cum-shot from the left that nearly caught Ridzuan Hasan unaware, although the Cheetahs keeper did well to keep it out at his far post.
In a last-ditch attempt to add more firepower up front, Bulls assistant coach Stephen Ng, standing in for the absent K. Balagumaran, decided to bring on towering striker Jung Hee-bong and hand 19-year-old Iqbal Hussain his debut.
And the move almost worked to perfection 12 minutes from time when the Hougang defence was split apart by a clever one-two between Jung and Durand, before the former clinically fired past Ridzuan at his near post. However, Gombak's celebrations were short-lived as the linesman correctly ruled it out for offside.
Right at the death, the hosts had one final chance to force a draw when they were awarded a freekick right on the edge of the area, but Vikraman was unable to keep his effort down, leaving Gombak with a task ahead of themselves when they travel to the Hougang Stadium on Saturday for the return leg.
Gombak United: Zaiful Nizam, Ismail Yunos, Obadin Aikhena, Walid Lounis, Nurullah Hussein, K. Vikraman, Adrian Dhanaraj, Christopher Anderson (Iqbal Hussain 88'), Mustaqim Manzur (Jung Hee-bong 63'), Hafiz Rahim (Fairoz Hasan 75'), Julien Durand.
Hougang United: Ridzuan Hasan, Lau Meng Meng, Syaqir Sulaiman, Stanislav Vidakovic, Fazly Hasan, Faizal Amir (Basit Hamid 70'), Azhar Sairudin (Hasree Zais 89'), Ante Barac, Jordan Webb, Fazli Jaffar (Sobrie Mazelan 82'), Mamadou Diallo.