The front three of Simon Wilson, Ben Clark and Lee Neilson caused Newfield early problems and it was no surprise when Steve Dobson raced in to turn home a weak, off-target shot from Clark.
John Senior hit the bar as the home side looked to hit back before the break.
Lion doubled their lead in the second half when good work from Si Wilson enabled Ian Wilson to score his third goal of the season.
Visiting keeper Stu Austin turned a Brett Beardsmore free-kick over the top before Lion hit a third, Si Wilson netting at the second attempt.
Richard Jackson's low 25-yard drive beat Austin to give Newfield a sniff but just before the end Si Wilson bagged his second following neat work from substitute Michael Robinson.
Lee Mulligan, Scott Roddis and Senior did well for Newfield while Si Moon, Craig Norton, Dobson and Ian Wilson were best for the winners.

Castleford Black Bull ..2
Anglers Athletic ...4
Castleford continued their lack-lustre start to the season with this home defeat against newly-promoted Anglers.
Athletic were quick to settle and Cas were grateful for a superb stop from keeper Gavin Smith. But early pressure told when Liam Watson brought down an Anglers striker, who made no mistake from the resulting penalty.
Gradually Bull got a foothold, thanks to the hard-working Rob Waring, but were extremely lucky when the visitors' keeper allowed a tame shot from Danny Forsyth to trickle through his legs.
But Anglers hit back within minutes as Watson and Chris Reavley sandwiched a striker to concede another penalty. The pair's clash of heads saw both leave the field.
With Terry Bailey tireless, the home team equalised for the second time when Bailey was dragged down in the box and converted the subsequent spot-kick.
But Anglers regained the lead from a long ball that Bull's back-line should have dealt with and a late own-goal from Steve Backhouse sealed the hosts' fate.
Best for Cas were Waring, Bailey and man of the match Smith.
Bull thanked Terry Kenny, landlord of the Black Bull, for his continued support and Paul Harris, of Steel Supplies Ltd, Doncaster, for this season's kit sponsorship.