Nathan Brown's first century in three years has pushed Lavington to the edge of the top six for the first time.
Brown plundered New City's attack in smashing 101 from only 92 deliveries, including four boundaries and an incredible seven sixes on Saturday.
He combined in a 140-run stand with Matt Tom (64) as the visitors posted a monster total of 5-286.
Tom then destroyed the home team's hopes by running out Shoaib Shaikh for 64 in the total of 173.
"Nathan was unbelievable, he's been brewing for a while to play another innings like that, we haven't seen that consistency for a couple of years and the way he batted showed how classy he can be," coach Daryl Tuffey enthused.
"He just played percentage shots, when they bowled a bad ball, he wacked it, he respected their good balls but was still able to hit them for singles and twos and that's the sign of a good batsman being able to get runs off the good balls as well, rather than dead bat it."
It was Brown's first ton since making 106 against North Albury in November, 2017.
It was only his seventh innings of the season and followed three single-figure scores.
Tom carried similar form into the round 14 clash, not making it past 10 in his last three knocks.
He struck his highest score of the summer from 112 balls.
"He's been a tad disappointing at the start, but he batted really well and both he and Nathan fed off each other," Tuffey said.
"Our batting unit fired, we're starting to find form at the right time of the year, I'm really happy with the direction we're heading after a pretty slow start."
A perennial finalist, Lavington had a horror start, winning just one from eight rounds, although that included two draws due to the wet weather and a bye.
Since falling to Belvoir, the Panthers have racked up four straight wins, with another draw and bye thrown in.
New City's hopes rested on Indian recruit Shaikh, who leads the run-scoring.
One of his first scoring shots was a six and he looked capable of clocking up a second successive ton, but was run out by a direct hit by Tom, who dived to stop the ball, got to his feet and ended not only the Phoenix's hopes, but realistically their slim finals chances.
IN OTHER NEWS:
A report is being prepared against Shaikh.
Panthers' quick David Tassell claimed 4-51.