The 2-1 win was the first time the Jets had opened the season with victory in five years and came after their round-one F3 derby with the Mariners one week earlier had to be abandoned due to a water-logged Central Coast Stadium field.
The result, however, came at a cost with Jordan Elsey red-carded midway through the second half after the experienced defender had scored the game's first goal 10 minutes earlier.
The game was all locked up at 1-1 until Georgian Beka Mikeltadze found an injury-time winner to the delight of the Newcastle faithful.
Next up for Newcastle is Wellington Phoenix on Saturday night. Elsey is likely to miss the next two outings at least through suspension with Matt Jurman his possible replacement.
Improved showing for Newcastle in Uni 7s
Newcastle rugby sevens player Peta Salter hailed her side's improved showing after they finished fourth in the latest round of the national university series held in Charlestown over the weekend.
"He really showed his maturity in this game," Belmont skipper Luke Muddle said of Gillard.
"From where he was last year to now, he's just taken a huge leap. It's a credit to him for working his arse off."
Belmont were tipped to struggle this season but Muddle predicted his side would cause some upsets.
At Lynn Oval, Stockton launched their premiership defence in style with a comprehensive victory over Hamilton-Wickham in a rematch of last season's two grand finalists.
Wests, University, Charlestown and Wallsend also took wins.
The 31-year-old from Lake Macquarie - who clinched her sixth successive world title at the tour's previous stop in Bari, Italy, in September - racked up 387.75 points to clinch first place as the high-dive spectacle made its first visit to Australia.