By Gabriel Tan
The Young Tigers had been unbeaten in their six previous games prior to Sunday's clash but went behind in the 12th minute when Shotaro Ihata clinically finished a flick-on from Frederic Mendy.
However, they hit back just after the break through a wonder goal from Ahmad Hazwan, although the Protectors eventually grabbed all three points when they Mendy grabbed a winner just before the hour mark.
Nonetheless, Ong remained upbeat despite the loss and believes it will serve to improve his players in the long run.
"Home United are an experienced side," Ong said after the game. "Even though my players have been playing together for a very long time, they are still boys.
"They have to learn a lot in terms of handling the situation when the score was 1-1. Overall, they tried very hard to come back after going down 2-1.
"They are not mature yet. They need to learn when they should cross and when they should get into the box, when they should pass and when they should dribble."
The pacy Harimau attack had been expected to pose severe problems for Home's defenders, who have been unconvincing all season long.
However, Protectors coach Lee Lim-saeng unusually fielded five man at the back, a tactic which paid off, and Ong admits the hosts had been tough to break down.
"Today [Sunday], the Home United defence looked very solid and worked very hard, especially with Lionel Lewis in goal."
One player Ong did single out for praise was Hazwan, who scored a spectacular goal when he stole the ball on the edge of the area, before unleashing an unstoppable effort past Lewis, and believes he could go on to better current Malaysia star Safee Sali.
"It was a superb goal, especially for a 21-year-old to have that ability," Ong gushed. "I've been rating him as our next top striker in Malaysia.
"With more international exposure, he will be even better than Safee."
And while many had expected some of the teams to take Harimau Muda lightly this season due to their relative youth, Ong believes their precociousness will make them even bigger targets.
"I think there are a few more teams what we're going to face that will pose a tough test to us, not just Home United," the former Malaysia international added.
"Every time we play, the opposition will play extra hard against us. It's boys playing against adults, and adults definitely don't want to lose against boys."
While Home coach Lee Lim-saeng insists his players deserved to win on Sunday night, he was quick to praise the intensity showed by the young Malaysian side.
"It was a tough game against Harimau, all of them are young and fit players," the South Korean said.
"I want to give credit to our opponents, who also worked very hard."
Harimau are next in action against Woodlands Wellington on Sunday, while Home have a bye in the next round of S.League fixtures after Wednesday's AFC Cup game against Yangon United.