The Magpies secured the signing of the 27-year-old from Stoke City on a three-year contract earlier this week.
The former Spain Under-21 international only managed four Premier League goals for Stoke during the 2015-16 campaign, before netting five in La Liga during a loan spell at Deportivo La Coruna last season.
Joselu was a regular scorer during his time in the Bundesliga, however, and Benitez has tipped the former Real Madrid youngster to finally 'fulfil his potential' with the Magpies.
"You've not seen too much of him at Stoke, but he's played in top leagues. He has a lot of potential. We've seen him playing for Stoke. He's played in the top leagues and he can score goals," Benitez told reporters.
Joselu could make his Newcastle debut in Sunday's Premier League clash with Huddersfield Town.