The striker came off the bench alongside Jamie O'Hara with the score at 0-0 and 70 minutes on the clock.
In doing so, Juande Ramos took off Ledley King and switched his system to three at the back and three up front as we went for the win at the Lane.
The changes paid off handsomely as Darren pounced with a close-range header to open the scoring 10 minutes later and then within two minutes, set up Jamie's side-foot home for 2-0.
"The manager is not scared to take a chance and it paid off," beamed Darren afterwards. "I'm more delighted with the three points than scoring the goal.
"The chance I scored from is a bread and butter chance for strikers, you live off those chances and I reacted to put it away.
"Then I played in Jamie for his goal and I was delighted for him to get his second goal for the club.
"I'd obviously like more minutes on the pitch but my confidence is right up there as long as I can keep coming on and doing what I know I can do.
"I have to keep coming on and make sure I help the team so we can climb the league."
Darren Bent was pleased to play his part in the win against Portsmouth.