Newcastle United have signed Kenedy, Martin Dubravka, Ki Sung-yeung and Fabian Schar so far this summer.
And the club is waiting on a work permit for Mainz striker Yoshinori Muto.
Benitez still wants to sign another striker, a No 10, a centre-half and a left-back before the August 9 deadline.
United’s manager is having to work within tight financial constraints, and yesterday’s £20million sale of Aleksander Mitrovic (pictured) is unlikely to change things given that Fulham are not paying all of the fee up front.
Benitez is understood to keen on Ajax left-back Nicholas Tagliafico, who went to the World Cup with Argentina this summer. Tagliafico – also reportedly a target for Fulham – is available for around £8million this summer.
The 25-year-old could be out of Newcastle’s price range.
Benitez also hopes to sign West Bromwich Albion striker Salomon Rondon, who has a £16.5million release clause in his contract at The Hawthorns.
A swap deal involving United striker Dwight Gayle has been discussed with the relegated club.
Benitez left Gayle on the bench against Porto at the Estadio do Dragao on Saturday.
Meanwhile, Mitrovic told of his “pride” after joining newly-promoted Fulham.
The 23-year-old had spent the second half of last season on loan at Craven Cottage.
“I’m very glad and happy and proud to finally be here and officially become a Fulham player,” said Mitrovic, who will take the No 9 shirt at Fulham.
“I’m happy to the moon and back. I have love for the fans.
“They’re amazing fans, and I have a really good connection with them.
“This is a big club, and last year we made history (by winning promotion).
“We did big things, and I want to continue this. We want to keep making big things, and with all the fans behind us, I think we can go far.”