Under-21 captain Alex Cook hadn't received much of an opportunity with the ball for Belmont this season.
But the right-arm seamer made the most of his latest eight overs, claiming two major Wallsend scalps to give Belmont a chance of defending 161 at Cahill Oval on Saturday and finishing the 2018-19 season with a win.
The visiting Tigers resume at 5-76 with key batsmen Jake Montgomery (12) and Nathan Price (4), both bowled by Cook late on day one, already back in the pavilion.
"A lot of our totals have been in the 100-to-150 category this season so we've only really bowled our frontline three - Jace [Lawson], Dan [Bailey] and Toby [Gray]," Belmont skipper Marcus Hainsworth said.
"There hasn't really been a lot of opportunity for anyone else. But with Dan out injured, Luke Muddle opened the bowling because he is a genuine swinger and then Alex [Cook] came on.
"He [Cook] got a bit of a chance and he took it. He got Mont and he got Pricey, both the top of off."
Wallsend went from 1-61 to 5-61 as lightning and bad light threatened to stop play, but it was the only last-round fixture in first grade that remained uninterrupted.
Hainsworth expected the Tigers to fight on day two.
"I've seen quite a few of their scorecards where they've won seven or eight down," he said.
Both sides are out of finals contention with Wallsend eighth and Belmont ninth on the Newcastle District Cricket Association ladder.