A second straight day of action at the Sentosa Golf Club was hindered by torrential rain, although at least this time around, the weather held up for all of the golfers to complete their final rounds.
And it was Pagunsan, starting the day five shots behind leader Gonzalo Fernandez-Castano, who produced some impressive golf, shooting a four-under-par round of 67 to take over the lead at the 18th hole.
However, Fernandez-Castano held his nerve by holing his par putt to stay level with Pagunsan at 14-under.
With clouds starting to threaten overhead, both players headed out to the 18th tee to continue their duel with a sudden-death play-off, but after teeing off, play was suspended due to lightning.
Following over an hour's wait, both players came back onto the course, hit their second shots, before play was once again called off.
And with no signs of the weather letting up, organisers had no choice but to postpone the play-off till Monday morning.
However, the rainy weather did little to ruin Pagunsan's spirits, with the 33-year-old vowing to make the most of the opportunity to win his first European Tour title.
"It's going to be more exciting tomorrow [Monday]," Pagunsan said. "It will be interesting.
"Confidence is getting stronger and stronger. I can't say what will happen tomorrow [Monday].
"We were almost the same distance [from the pin] - we don't know what will happen."
However, one thing Pagunsan had been certain of was his ability to pull level with Fernandez-Castano, after he had climbed to just one shot behind with one hole to play on his round.
"When I saw the leaderboard on the 17th hole, I was just one shot behind and I told my caddie to give myself a chance to tie the leader on the 18th.
"I just tried hard to win. I hit the third shot from 85 yards over the pin and spun it back. [Then] I made a good putt - it was from about six or seven feet."
Having then spent a few nervous moments waiting for Fernandez-Castano to finish his round, Pagunsan admits he thought he had won it after seeing the Spaniard hit his tee shot into the water.
However, Fernandez-Castano saved par with a brilliant long putt, which ultimately ensured both men will be back in action again on Monday morning.
"I saw that Gonzalo's drive was in the water [and] in my mind, I though I was going to win, no play-off.
"But he made the putt also [but] I'm still here and will wait for a result tomorrow [Monday]."
And whether or not he takes home the grand prize of US$1million on Monday, Pagunsan believes there are many positives he will take from his impressive performance at the Sentosa Golf Course.
"I'm really happy with how I played. Even if I win or not, I've already saved my card for next year.
"I'm really happy, but I'm hoping to win tomorrow [Monday].
"I'll go back now and get ready again for the play-off."
Should he win the Barclays Singapore Open, Pagunsan will be the first Filipino to record a win on the European Tour.