By Gabriel Tan
Despite many expecting them to ease past the Bulls at the Jalan Besar Stadium, Harimau found themselves two goals down by the 64th minute courtesy of goals from Zulfadhli Emran and Jung Hee-bong, before Wan Zack Haikal pulled one back from the spot two minutes later.
Gombak's first goal came after captain Mahalli Jasuli gave away possession from a throw-in, allowing Zulfadhli to stride forward and net with a low shot that Izham Tarmizi should have done better with, before the Harimau custodian was easily outjumped by Jung, who nodded a back header into the unguarded net.
Speaking after the game, Ong admitted that the pressure of challenging for the title was starting to get to some of his players, but was adamant they had done themselves no favours.
"Of course I am disappointed with the result," he told ESPNSTAR.com. "The title race is making things a little bid hard for the boys.
"They know they have to produce and win all the matches, and I think it's affecting them a little.
"We made two silly mistakes that led to Gombak's goals. It's still easy to come back from one goal down, but to make another silly mistake and have to come back from two goals behind makes it very difficult.
"We made it easy for Gombak to sit back after that, which is what any team would do with a two-goal lead. Gombak played to their strengths and moved the ball well from the middle third to their attackers, but for me, their goals were from our mistakes."
Ong also admitted his side's finishing was not at its best on the night, given they had a series of good chances to open the scoring in the first half.
"It was down to a matter of finishing tonight [Sunday]," he added. "We had our chances and should have wrapped up the match in the first half.
"When you don't convert your chances, the opponents get more confident and we should have finished the game in the first half. It would have made it more comfortable."
The ex-Malaysia international did however believe the fact that Harimau did not get a chance to train on the artificial turf at Jalan Besar played a part in their defeat, after they turned up at the stadium on Friday only to get turned away because Malaysia Super League outfit LIONSXII were already having a session, which appeared to be an error on the part of the Football Association of Singapore (FAS).
"We didn't get a chance to train on this field, which made it very difficult," Ong added. "No matter how good you are, you need a day or two to acclimatise.
"I'm not making excuses but when you play on artificial turf, it's different.
"We have to find a proper way to communicate. We tried our best but the boys have to learn. Now we have look forward and rectify the matter, whether on our part or the Association's."
Gombak coach K. Balagumaran hailed the impact youngsters Ahmad Suhaimi and Zulfadhli Emran had after handing both of them chances to impress from the start, and even hinted the latter could replace the void left by anchorman Adrian Dhanaraj, who was recently diagnosed with Hodgkin's lymphoma.
"Personally, I feel good," he said. "In the first game [against Harimau] we were beaten 2-0 but that game taught us a lesson.
"From there, we came up with our game plan, it worked and the key thing is that every time we bring in young players, they rise to the occasion and play extremely well.
"Today [Sunday], Ahmad and Zul did just that. Ahmad did a very good job today [Sunday]. We are still trying out players for Adrian's position and Zul did very well and even scored a goal."
Balagumaran also had good things to say about Jung, who has struggled for form throughout the season, and rated Sunday's victory as one of the best in the campaign alongside the 1-1 draw they recorded against DPMM FC in Brunei.
"We brought Bong in and for the first time, he actually jumped high and headed the ball to score," he added. "I was really happy for him and he made a difference. Tactically, he's doing what we tell him to do.
"Personally, I think this is one of our best performances, like the one against DPMM in Brunei. Each individual gave their best and I have nothing to criticise of anyone."
The Bulls now turn their attentions to their RHB Singapore Cup semi-final clash against SAFFC this week, and their boss admits the victory over the Young Tigers will give them a huge boost ahead of the two-legged encounter with the Warriors.
"Our spirits are very high ahead of the Singapore Cup," Balagumaran revealed. "I saw the players' reactions and this result was certainly a big boost.
"I always believe that you can do all the planning but so many factors play a part. On the day, the better team wins."
The first leg of Gombak's last-four clash with SAFFC is on Wednesday at the Choa Chu Kang Stadium, before both sides meet again three days later at the Jurong West Stadium.