"We missed some targets at the beginning and I think we are paying for that ..." "I'm not happy with it, but at the same time, for me, it's a challenge and I will try to do my best. The team spirit's quite good, and hopefully we replicate that this season".
But Benitez is unhappy that other Newcastle targets have been missed although he admitted that it has been hard.
Former Liverpool boss Benitez has endured of hard summer, having been frustrated in his attempts to bolster a squad that won The Championship last season.
"I'm not totally happy with what we did, but I will try to do my best".
"Sometimes it is not about you want, it is about what you need and what you can afford now", he said. Average players now cost big money. "We will continue to fight because the truth is that he [Perez] is looking forward to joining us".
There was a rumour of a power struggle at Newcastle regarding player recruitment.
"No, I made a decision to stay", said the 57-year-old.
The former La Liga striker moved to Arsenal last summer in a four-year-deal for £18million, but Perez failed to find a regular spot in Arsene Wenger's senior squad.
Having impressed for Sunderland, the combative engine room operator controversially crossed the Tyne-Wear divide back in the summer of 2014, when Alan Pardew brought him in on a free. "At the end of last season, Mike Ashley said he would give every penny he had to Rafa".
"I know that he did really well. But with his experience and know-how, he will set the team up to be very hard to beat".