Fenton's head knock allowed Michael Boxall to have his first start of the season having made nine previous appearances from the bench.
The Hutt Recreation Ground was given its second opportunity to masquerade as an A-League venue as Westpac Stadium remained unavailable due to the Cricket World Cup.
The Lower Hutt ground is home to club cricket during the summer but it has been transformed in recent weeks and will host one more game next month before the Phoenix return to the Cake Tin.
Despite hardly touching the ball during the opening stages, Newcastle found themselves with a two-goal lead after 18 minutes thanks to an own goal at a corner from Phoenix midfielder Roly Bonevacia and a Scott Neville header.
The Jets arrived in Wellington at 11.30pm last night after they took the late flight in to the capital, which didn't seem like the ideal preparation for a game.
The club have also been embroiled in problems off the field, with a player revolt, sackings and management issues plaguing the Novacastrians recently.
Despite their issues, they've managed to remain competitive on the paddock in the past few weeks, although they still occupy ninth place on the A-League ladder.
Despite Wellington's lack of goals in the past fortnight, coach Ernie Merrick remained defiant that his side were on the right track, the ball just wasn't falling their way.
The Scotsman said his men needed to keep plugging away and eventually the dam would burst.
Merrick's team seemed determined to test that thinking as they continually found ways to miss chances during the first hour of the contest.
Nathan Burns, who could have sent the crowd of 8437 home with free pizza due to a sponsor's promotion if he scored, couldn't finish from close range, while Fijian international Roy Krishna overcooked a couple of opportunities.
Krishna eventually broke through in the 68th minute as the home side got on the board but the chances continued to go begging as the game wore on.
The Jets were reduced to 10 men for the final minutes when Ben Kantarovski was shown his second yellow card, which gave further hope to the Phoenix; enter Hicks, who scored when his side needed him most.
Wellington will next meet the Victory in Melbourne on Sunday.
Wellington Phoenix 2 (Roy Krishna 68, Jason Hicks 90+4) Newcastle Jets 2 (Roly Bonevacia 12 own goal, Scott Neville 18) halftime: 0-2