The Power finished with a flourish, kicking the last four goals for a plucky 10.13 (73) to 7.10 (52) win at Adelaide Oval on Sunday night.
North could have risen to eighth with a win. Instead, they remain 11th with concern over Wardlaw's left hamstring injury.
"We'll get that assessed during the week," Kangaroos coach Alastair Clarkson said.
"We'll just deal with it."
Wardlaw, who had a delayed pre-season due to hamstring issues, hobbled off in the final quarter as the Roos were overwhelmed by the Power.
After leading by a goal late in the third term, the Kangaroos added just one point in the last term for another miserable trip to Adelaide Oval, where they have lost 15 from 15 games.
"Our season's still alive," Clarkson said. "There's a logjam of teams around the middle of the ladder.
"I'm sure Port would have been a little bit twitchy at three-quarter time.
"But to their credit, they got the whips cracking in the last quarter and got the ascendancy."
Port's attacking duo Mitch Georgiades and Jack Whitlock kicked three goals each in another miserly defensive effort from their team.
Under first-year coach Josh Carr, the Power are 15th but rank second for points against. Only ladder-leaders Sydney have conceded less.
"The first half lacked a bit of energy in the game," Carr said. "I didn't think we were poor but we weren't great at the same time.
"And to the boys' credit, at three-quarter time, I think everyone knew what we had to do and a number of players stepped up and played a really good last quarter."
Port's Jason Horne-Francis (24 disposals, nine clearances) was excellent against his former club, and acting captain Zak Butters (26 touches) and veteran Darcy Byrne-Jones (24) were again influential.
North's Harry Sheezel, a week after collecting 43 disposals, gathered 40 and a goal.
Sheezel's midfield mates Luke Davies-Uniacke (21, one goal) and Colby McKercher (28, one goal) were also standouts while veterans Luke Parker (27 touches) and Jack Darling (two goals) proved valuable.
Both clubs scored just one goal in a dour opening term before Port kicked four to one in the second, for a 5.5 to 2.5 halftime edge.
Port skipped 25 points clear when Georgiades slotted his third major two minutes into the third term.
But just when the Kangaroos appeared down and out, they responded with an unheralded scoring spree of five consecutive goals.
Scores were locked 7.9 apiece at the last break before a desperate goalless dozen minutes.
But a classy snap from Corey Durdin was the first of three Port goals that sealed victory before 33,105 spectators.
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