Speaking on the talkSPORT Breakfast Show, the ex-Sunderland striker was asked for his view on the 24-year-old Brazilian, who has netted just three Premier League goals since joining the Magpies back in 2019.
Bent claimed: "He does work really hard, and it's a bit unfair (giving him stick)... they've signed him for a lot of money, and people knew before he got there that he's not a regular goalscorer - he wasn't prolific at all.
"But people still judge him because of the price tag, and he does work really hard and put he shift in. He has been better of late, but if people were expecting him to get 10 to 15 goals (this season) it was never going to happen, because he wasn't doing that before he got there."
Meanwhile, Bent was asked by presenter Alan Brazil whether, with Sheffield United and West Brom all but down, Newcastle and Brighton were in a straight shoot-out to avoid the final relegation spot.
The former England international revealed: "I would have said that... but Brighton ...it was a massive result from them (beating Southampton).
"I think Newcastle have got big problems, but they've halted it a bit. They've picked up a couple of positive points and they've got big players to come back.
“The quicker they can get Saint-Maximin, Almiron and Callum Wilson back... and they're still above the relegation zone, they'll give themselves a great chance (of survival).”