Mirco Mueller, Manraj Hayer and Joshua Winquist also scored for the Silvertips (1-2-1).
John Neibrandt, Trevor Cheek, and Tristan Sieben each scored their first goals as members of the Giants (0-3-0), while Jackson Houck chipped in with two assists.
Austin Lotz stopped 34 shots for win as Liam Liston allowed four goals on 13 shots before getting pulled early in the third period. Tyler Fuhr came on in relief and stopped 7-of-8 shots in his WHL debut.
Liston is still looking for his first win as a Giant, his third WHL team in as many seasons.
Everett went 0 for 1 on the power play while Vancouver went 1 for 3.
After Everett and Vancouver swapped first-period goals, the visiting Silvertips got two goals 22 seconds apart early in the second period.
Petryk took a pass from Ryan Murray and put one by Liston’s outstretched glove at 1:54.
Then at 2:16 the Silvertips made it 3-1 after a turnover led to Hayer scoring from in front of the net.
Cheek helped the Giants cut the deficit to one goal on a power play. He let go a hard wrist shot from a little inside the blue line.
The Giants outshot the Silvertips 30-11 in the opening two periods but trailed entering the third.
At 1:54 of the third Petryk took advantage of a puck that bounced over the stick of defender Brett Kulak as he went in alone and lifted a backhand past Liston for his second of the game.
With 12 minutes to go in the third the Giants drew back within one. Vannieuwenhuizen’s point shot was deflected by Sieben at 8:06 for his first of the season.
Just after Lotz made a big save to keep his team up by one Winquist got in on Fuhr and beat him with a backhand-forehand move, to restore the two-goal cushion.