A week after crossing three times in the victory at Castleford, the England winger repeated the act to help his side leapfrog their opponents in the table.
The Giants were the dominant force for much of the opening period and thoroughly deserved their 30-10 interval advantage.
Within five minutes in-form Lee Gaskell sent Jordan Turner clear to feed Jordan Rankin to finish off. Danny Brough made no mistake, adding the first of his five first-half conversions.
Trinity waited just three minutes to find their response, Ryan Hampshire’s kick to the corner finding Ben Jones-Bishop to finish off. Hampshire then landed the touchline goal. The visitors did not help their cause when Matty Ashurst was sin-binned for dissent and just before he returned to the fray Brough fed Alex Mellor to crash over from close range.
Leroy Cudjoe teased the Wakefield defence before finding McGillvary to show great strength to squeeze in at the corner.
Bill Tupou respnded with a try in the 24th minute, but two Huddersfield tries, from Darnell McIntosh and McGillvary, the latter’s 150th for Giants, made their task even tougher.
Four minutes after the break he scored try No 151.
The Giants’ seventh try came from Ukuma Ta’ai, Brough’s goal bringing up the 40-point mark.
Jacob Miller’s kick to the corner paved the way for Pauli Pauli to score with the minimum of fuss. Hampshire’s conversion made it 40-16 then Justin Horo crashed over for another converted score. Tom Johnstone’s try, which Hampshire converted, completed the scoring.